SBI 189

SINGLE FAMILY HOUSES SBI 189
Insulation – moisture protection, acoustics, fire resistance, ventilation and strength.

2nd EDITION SBI-DIRECTION 189 STATENS BVGGEFORSKNINGSINSTITUT 1999

Translation from Danish to English: Karsten Lundager and Roger Taylor

Contents
Preface ....................................... 9

Crawl space external walls ........ 30 Crawl space internal walls ........ 31 Crawl space deck ........................ 32 Timber joists ............................. 32 Concrete and clinker concrete deck ................................................ 33

Introduction ............................ 10 Basements .................................. 36 Thermal prevention ................. 36 Load and load acceptance ....... 12 Basement floor ......................... 36 Terrain classes for wind.............. 12 Basement external walls ............. 36 Stabilising system ...................... 13 Dimensioning ......................... 38 Dimensioning and design............ 14 Heat insulation ......................... 39 Moisture insulation ................ 40 Foundations .............................. 15 Internal basement walls ................ 40 Foundation classes ................... 16 Deck over basement .................... 40 Low foundation class ................ 16 Timber joists................................. 40 Dimensions ............................. 17 Concrete and clinker concrete deck 42 Workmanship ............................. 18 External basement stairway ......... 42 Inserts or recesses . . . . . . . . ...... 19 External walls ........................... 44 Concrete .................................. 19 Thermal insulation ................... 44 Hollow foundation blocks and Moisture conditions .............. 44 solid Fire precautions ....................... 46 light clinker concrete blocks.... 19 Passage of sound...................... 46 Heavy external walls .................... 46 Drainage .................................... 20 Examples of heavy external walls Workmanship ............................. 20 ... 47 Branch drains ......................... 21 Light external walls .................. 48 External basement walls ......... 21 Other external walls .................. . 49 Cleaning ................................ 21 Fitting windows and external doors Drainage ............................... 22 . . . 50 Protection against rats............... 23 Window and door lintels ....... 50 Fascines .................................. 23 Joints ....................................... 50 Ground supported floors .............. 24 Internal walls ............................. Ground conditions ................ 24 Thermal insulation ................... Capillary breaking layers ...... 24 Fire conditions ....................... Heat insulating layers .............. 24 Passage of sound...................... Concrete slab........................... 24 Strength properties ................... Floor finishes ........................... 24 Radon proofing ...................... 25 Walls between joined houses *) Examples of ground supported floors 25 Passage of sound ......................... Crawl space ............................... 29 Ventilation.................................. 30 Crawl space floor ........................ 30 54 54 54 54 55 56 56

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Solid walls................................ Double walls .......................... Noise from installations ........ Fire precautions ..........................

Water and drain installations . 82 56 57 Floors ......................................... 82 59 Heavy floor constructions......... 82 59 Light floor constructions........... 83 Walls .......................................... 84 Roofs ........................................ 60 Tunge walls ............................. 84 Thermal insulation.................... 60 Light walls............................... 84 Moisture conditions .............. 60 Ceilings...................................... 85 Fire protection ........................ 60 Joints.......................................... 85 Roof coverings, underlay and battens .................................................... 61 Glass ....................................... 86 Underlay roofs ......................61 Glass types ................................. 86 Battens ..................................... 61 Permissible glass area................. 86 Concrete and clay roof tiles . 61 Thermal stress............................. 87 Slates ....................................... 61 Impact........................................ 87 Profiled roofing sheets............. 61 Preventing cutting injuries ..... 87 Roofing felt .............................. 62 Glass as a safeguard . . . . . . . . . 87 Rafter and ceiling construction .. 62 Conservatories ......................... 88 Collar beam rafters ................ 63 Glass roofs ................................. 88 Trussed rafters ....................... 63 Common rafters/joists ............. 63 Indoor climate ........................... 89 Roofing elements ..................... 65 Ventilation .................................. 89 Gable triangles............................ 66 Ventilation principles ............ 89 Roofs with trussed rafters......... 67 Natural ventilation ............. 89 Roofs with collar beam rafters.. 67 Mechanical ventilation ....... 90 Functional requirements Thermal insulation .................... 70 general.................................. 90 Three possibilities.................... 70 Habitable rooms....................... 90 U-value requirements ................... 70 Kitchen, bath room and toilet .. 92 Heated floor area and heated Other rooms, crawl footprint area ........................ 71 space/basements . 92 Heat loss frame............................ 72 Fresh air vents and ventilation Temperatures ........................... 72 ducts . . . 92 Transmission areas ................ 73 Fresh air vents ...................... 92 Possibilities - using Heat Loss Ventilation ducts ................... 93 Frame. 73 Pollution from building materials 94 Examples Heat Loss Frame used Danish Indoor Climate Labelling 95 on single family house.................. 74 Heat producing appliances and Energy Frame ............................. 75 chimneys ................................ 96 Possible window and door area . . . Heat producing appliances.......... 96 76 Setting up ................................ 96 Temperature conditions (in Connection to chimney ............ 97 summer). . 78 Chimneys.................................... 97 Cross-sectional area ................. 97 Wet rooms .............................. 79 Height ..................................... 98 Requirements to wet rooms........ 79 Construction ............................ 99 Zoning .................................. 79 Thatched roofs ........................ 99 Floor slope .............................. 79 Waterproofing........................... 80

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Enclosure A. Loads *) ............. Gravity based load .................. Wind load.................................. Design load ........................... Example.................................

101 101 102 103 103

Enclosure B. Fire ................... 105 Fire resistance - building components .. 105 Fastening of mineral wool ....... 105 The fire-technical qualities of claddings (coverings) Class 1 covering .................. 106 Class 2 covering .................. 106 Enclosure C. Acoustics ............ General ..................................... Luftlydisolation ......................... Trinlydniveau ............................ Installationsst0j ....................... Trafikst0j................................... 108 108 108 109 109 109

Data of the building ............... 127 Ventilation ............................. 129 Heat loss ............................... 129 Time constant......................... 129 Internal heat contribution ....... 129 Heat demand........................... 130 Energy Frame ....................... 131 Calculation form 1. External walls, Roofs and floors ........................ 132 Calcualtion form 2. Windows and external doors……………………………… …… . 132 Calcualtion form 3. Insolation.... 132 Shadow factor ...................... 135 Area factor ............................. 136 Glass factor ......................... 137 Example: Heat demand in single family house 137 Summary ............................... 141

Enclosure D. The stabilising system ................................................ I ll Bracing the roof plane ............... I ll Vertical anchoring of roof ......... I l l Type classification and dimensioning of anchors.............................. 112 Embedding anchors................ 114 Design of ceiling diaphragm .... 115 Panel cladding ...................... 115 Design of bracing walls ........... 118 Vertical anchoring ................ 119 Solid walls.............................. 119 Stud walls............................... 123 Dimensioning bracing walls and ceiling diaphragm ................... 123 Windload on ceiling diaphragm .............................................. 123 Choosing bracing walls .. 123 Distribution of horizontal loadt ..............................................124 Dimensioning bracing walls ................................... 125 Non-bracing walls .................. 125 Dimensioning ceiling diaphragm .............................................. 126 Enclosure E. Heat requirements ................................................127 Heat requirement for a building, main table……………………………… ….. 127

Note: Chapters marked with *) are not yet available in this English version

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Preface
This SBI Direction is complementary to Building Regulations for Small Dwelling, 1998 and replaces SBI Direction 147: Constructions in small house, which was complementary to Building Regulations for Small Dwelling, 1985. The Direction also replaces SBI Direction 111: Thermal insulation of buildings, 2nd edition. The Direction covers such issues as thermal insulation, moisture insulation, sound insulation, fire, wet rooms, indoor climate as well as strength and stability. As the Direction covers a wide range of subject matters is has been necessary to call upon a wide range of specialist SBI writers. Apart from the project manager, civil engineer Jørgen Munch-Andersen, the following have also participated: Academy engineer Søren Aggerholm, academy engineer Niels Christian Bergsøe, civil engineer Erik Brandt, academy engineer Mogens Buhelt, civil engineer Henry H. Knutsson, academy engineer Peter A. Nielsen and architect m.a.a. Hans Zacharias-sen. The extensive editing work has been carried out by civil engineer Jens Christian Ellum. Several technicians within the Danish building industry have contributed with valuable information. We are very grateful for these contributions. The elaboration of the Direction has received support from By- og Boligministeriel og Energistyrelsen. (Ministry of Housing)

The target group of this Direction is engineers, architects, contractors and other designers and executors within construction. Also public administration is a target group. Supplements to the SBI Direction will be published at the SBF homepage http://www.sbi.dk. SBI STATENS BYGGEFORSKNINGSINST ITUT Department of Building technique and Productivity, June 1998 Georg Christensen, Research manager Preface to the 2nd edition This is the 2nd edition of SBI Direction 189 concerning »Single family houses«. Compared to the 1st edition a few changes and additions have been made. These are to large degree based on a dialogue with practice which has taken place during a number of seminars where the Direction has been presented. In relation to that SBI would like to express its gratitude for all received suggestions and comments for improvement. SBI STATENS BYGGEFORSKNINGSINST ITUT Department of Building technique and Productivity, November 1998 Georg Christensen, Research manager

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Introduction
This SBI Direction contains guidance on and examples of constructions in one family houses. The examples all comply with the requirements laid down in “Building Regulations for Small Dwellings, 1998 (BRS 98) The Direction covers detached as well as semidetached one family houses up to 2 storeys and a basement, as shown in figure 1. The maximum height above ground level is 8.5 m, measured from the ridge. It must be stressed that the examples shown in this Direction should be considered as examples, and alternative solutions fulfilling the requirements in BRS 98 are acceptable. An example: The dimensions stated for load bearing and bracing constructions may in many cases be reduced considering the actual conditions under which they are carried out. This, however, requires dimensioning by an engineer. Reference to other existing literature is either done by full reference in the text (written in italics) or simply by referring to the list of literature at the back of the Direction (only in the Danish Version). The Direction starts with a short introduction to the load-bearing and bracing system with special emphasis on load acceptance. In enclosure D, The Bracing System, it is shown how the bracing necessary to secure the stability of the house can be designed and dimensioned,. Different parts of the house are accounted for. Examples of building components are shown; their design and how they are connected to other building components. In the connection details special emphasis has been put on demonstrating how heat and moisture insulation can be carried
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out in a satisfactory way and at the same time fulfilling the requirements concerning fire resistance and sound insulation. In the shown examples it will in many cases be possible to substitute mineral wool with other insulation materials but care must be taken that the fire resistance requirements are met. Dimensions are stated for usual constructions. Alternative constructions may be dimensioned using the loads stated in enclosure A, Loads. The U-values in the shown examples fulfil the requirements of U-values stated in BRS 98, which are also the basis for determining the Heat Loss Frame for the house. In the chapter Heat Insulation it is discussed how the Heat Loss Frame and the Energy Frame could be used as a tool for choosing constructions with other Uvalues. In the chapters Wet Rooms and Glass examples of fulfilment of BRS 98 requirements in the said areas are shown. The chapter Indoor Climate primarily describes the establishment of satisfactory natural ventilation in one family houses. Issues related to stoking are treated in the chapter Fire Places and Chimneys.

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Ground floor

Ground floor

1 storey with ground supported floor Basement 1 storey with basement

Attic

Attic

Ground floor

Ground floor

1½ storey with ground supported floor

Basement

1½ storey with basement

1st floor

1st floor

Ground floor

Ground floor

2 storeys with ground supported floor

Basement

2 storeys with basement

Figure 1. The Building Regulations for Small Dwellings encompasses one family houses up to 2 storeys and a basement. The houses may be detached or semidetached. The Regulations do not apply to houses with separate dwellings divided by a storey partition (horizontal division).

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Loads, load acceptance and load transmission
Houses shall be built in such a way that they can accept and transmit occurring loads. The loads can be divided into: • Gravity based loads, i.e. the dead load of building components, the imposed load (furniture and people) and snow load. • Wind action Wind acts primarily perpendicularly on the surfaces of the house. The external walls and the roof surfaces at the windward side are exposed to pressure. The other surfaces are exposed to suction. Usually, the acceptance and transmission of gravity-based load do not present major problems. However, one must be aware that load-bearing walls are affected by horizontal wind action and vertical load simultaneously. The acceptance and transmission of wind

action require a stabilising system, which is described briefly in the following. Figure 2 shows the most important types of collapse, which must be prevented by the use of a stabilising system. Terrain classes for wind The force of the wind action depends among other things on the type of the terrain surrounding the building. In The Code of practice for Loads for the design of structures (DS 410) three terrain classes are defined. In the Code these classes are referred to as Smooth, Agricultural and Built- up, see table 1. Most new constructions shall be dimensioned for wind action according to the terrain class Agricultural . In an area with low buildings surrounded by farmland the wind action will only be reduced to a level corresponding to terrain class Smooth some 500-600 m inside the built-up area.

a)

b) c)

d)

e)

f)

Figure 2. The stability of the house is ensured by anchoring the various structural elements to each other. The roof trusses must be braced to prevent them from cascading (a) and anchored against horizontal forces (b) and upward-acting forces (c). The walls must be supported at the top by the ceiling diaphragm (d), and this must be able to transmit horizontal forces to the windbracing walls. In ome cases, the walls must also be anchored at the bottom to prevent sliding (e) and collapse or lifting (f)

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SBI-Direction 186: “Stability of small houses” gives a more detailed description of terrain classes and of the possibilities to utilise the wind action’s dependency on the actual shelter conditions in connection to wind from various directions. Table 1 Definition of terrain classes according to “Loads for the design of structures”. The description applies to the surrounding terrain. Terrain class Smooth Description of terrain

Transverse wall

Facade

Gable

Transverse wind action

Smooth terrain e.g. aquatic areas and moors without shelter. Agricultural Farm land with wind breaks, farms with gardens etc. Built-up Built-up areas or woodland.

Figure 3. Wind acting transversely: The gables and internal transverse wall may act as bracing walls.
Longitudinal wall

Stabilising system The central parts of the stabilising system are the bracing walls and the so-called ceiling diaphragm . Some important terms are indicated on figures 3 and 4. The ceiling diaphragm supports the external walls at the top and furthermore transmits horizontal forces from the roof including the gable triangles. The ceiling diaphragm must be able to transmit these forces to the bracing walls, which may be internal walls as well as external walls. Consequently, the ceiling diaphragm must be fixed to all external walls and to the internal bracing walls. Further, the ceiling diaphragm must be sufficiently stiff in order to secure that forces can be distributed to the braced walls without causing fatal deformations, see figure 5. The stabilising system must be able to transmit the forces to the foundation or floor slab. This will often require a protection against sliding and /or anchoring against upward-acting forces on the walls In addition, the roof construction itself must be braced and anchored to prevent failure as shown in figures 2a-2c. Failure as shown in figure 2c is caused by the considerable lifting force occurring as a result of the longitudinal wind (along the roof).
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Longitudinal wind action

Facade

Figure 4. Wind acting along the house: The facades and the internal longitudinal walls may act as bracing walls.

Wind

Figure 5. The ceiling diaphragm shall be adequately strong and rigid in order to distribute the wind action to the bracing walls.

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Dimensioning and design The dimensioning of load bearing and stabilising structures usually requires the assistance of an engineer. Enclosures A and D can be used to assist when dimensioning. Enclosure A, Loads, gives loads used in dimensioning structural elements affected by vertical action perpendicularly to their plane.

The chapters concerning the specific construction elements give examples of designs with sufficient strength to transmit the forces. Enclosure D, Stabilising system describes how the stabilising system in 1-and 1½ storey single length houses with pitched roof can be designed and dimensioned.

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Foundations
Foundation includes dimensioning and construction of foundations i.e. the structural elements that transmit load from the house to firm bearing stratum. Examples of foundations for various types of buildings are shown in figures 6,7 and 8. This chapter only applies to the construction elements accentuated in these figures. The remaining elements are discussed in subsequent chapters.

Level of topsoil excavation

Level of topsoil Level of topsoil excavation excavation

Excavation trench profile

Figure 6 Foundation at ground supported floor. Normally in situ cast concrete as a deep strip foundation is used (cross-hatched in the figure). The upper part is often built using clinker concrete blocks. Hollow concrete blocks may also be used especially where the topsoil excavation level is below the topside of the deep strip foundation, thus avoiding the use of formwork for casting the upper part of the foundation. The foundation shall have at least the same width as the wall above and should be symmetrically placed below this. The figure also shows the placement of a perimeter drain and a branch drain, which connect the capillary breaking layer beneath the floor with the perimeter drain. It is not necessary to connect the branch drain directly to the perimeter drain.
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Figure 7 Foundation at crawl space. Often a concrete pad is cast in situ (cross-hatched in the figure) and the crawl space wall is then constructed using clinker concrete blocks or hollow concrete blocks cast with concrete. The wall can also be cast fully or partly in situ, i.e. to the topsoil excavation level. The foundation shall have at least the same width as the wall above, and it should be symmetrically placed below this.

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Figure 8 Foundation at basement. Usually a concrete pad is cast in situ (cross-hatched in the figure) and the basement wall is then built using clinker concrete blocks or using hollow concrete blocks cast with concrete. Alternatively, the entire wall can be cast in situ. The foundation pad shall have at least the same width as the basement wall and it should be symmetrically placed below it. The figure also shows the placement of a perimeter drain and a branch drain which connect the capillary breaking layer under the floor with the perimeter drain. Foundation control classes Foundation work must comply with the directions given in Foundation Engineering DS 415 in which 3 foundation control classes are defined: Low, normal and high control class. In the present SBI direction, it is assumed that the control class is low. This class only comprises small and simple foundations on virgin and stable stratum above the water table. Such foundations can under certain conditions (as mentioned in the following) - be constructed based on empiric knowledge and without prior geo-technical surveys. If these conditions are not fulfilled the foundation shall be constructed according to normal or high foundation control class. In such cases geo-technical surveys of the sub soil shall be undertaken. Likewise, design as well as implementation control shall be carried out by experts. In such cases, we refer to the more extensive treatment of foundation problems in SBI-Direction 181: “Foundation of smaller buildings”.

Excavation trench profile

Low foundation control class
Foundations shall be constructed to a dept where they will rest directly on firm bearing stratum. That is usually a packed mixture of clay, sand and stone (called moraine clay by geologists) formed before or during the last Glacial Period. However, a bearing stratum
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can also consist of packed sand, gravel or coarse silt (called non-cohesive soil). If the bearing stratum is deeper than app. 2 m, it will usually be expedient to let an expert carry out the actual design work. When inspecting finished excavations, it must always be verified that foundation is carried out on firm and stable sediments. This inspection must be carried out by a person who possesses adequate geological and geotechnical knowledge. The local building authorities will in many cases demand to inspect the excavation before casting the first foundation. Likewise, the authorities may demand inspection of other parts of the construction. Usually the following soil layers are not considered stable: Fill, soil which has been excavated before or frozen soil, sediments with content of organic material e.g. turf, mud and certain special fat clays. The latter is characterised by not containing sand or stones and by having a high water content (25-40%), and by the fact that they sometimes crack. Such very fat clays are found in the western part of Funen and in the eastern part of Jutland .e.g. by the Little Belt, by the fjords in eastern Jutland and in the area around Skive.

Apart from resting on a bearing stratum, foundations shall be constructed at least to frost-free depth. Regarding external wall foundations, frost-free depth is usually 0.9 m below the surface. However, with special soil conditions such as silty soil the depth may have to be high. Silt is a soil type with grains rougher than clay but finer than sand. In low foundation control class there must be no digging below the level of the water table. It is therefore important to ensure that the water table is deeper than the planned level of foundation before starting the excavation. The excavation must not constitute any risk of damages to neighbouring buildings, sewer and supply lines, public traffic areas or similar. Thus, conditions in the neighbouring areas can in some cases exclude foundation work according to conditions in low foundation control class.

Dimensions
Based on the above presumptions deep strip foundation can be carried out without further investigations - using the values found in table 2.

Table 2 Dimensions of deep strip foundation under walls in small single length houses. The dimensions given require that the width of the house is less than 9 m. Width of deep strip foundation in m Under load-bearing and Under load-bearing internal walls non-load-bearing external walls 0.20 0.30 1 storey with ground supported floor 0.20 0.30 1½ storeys with ground supported floor 0.25 0.30 2 storeys with ground supported floor 0.25 0.30 1 storey with crawl space 0.35 0.30 1½ storeys with crawl space 0.35 0.35 2 storeys with crawl space 0.25 0.35 1 storey with basement 0.35 0.35 1½ storeys with basement 0.40 0.40 2 storeys with basement The foundation height should be chosen to at least 0.30 m under load-bearing internal walls. However, in houses with ground supported floor, at least 0.20 m. Brickwork chimneys and fireplaces require a foundation of the same height as stated for the deep strip foundations. Type of house
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The dimensions are valid for traditional single length houses that is, houses with loadbearing facades and possible load-bearing longitudinal walls placed close to the centre line of the house. Deep strip foundations shall have at least the same width as the wall above and should be placed symmetrically beneath this. In houses with basement where the foundation is used as abutment for the concrete slab in the basement floor, the foundation shall be at least 0.10m wider than the basement wall. This will usually be fulfilled if the width is chosen to 0.50m. Non load-bearing internal walls can usually be founded directly at the floor deck concrete slab. The maximum linear and point loads, which can be transmitted, depend on the concrete slab and the insulating material. Reference is made to product catalogues from the insulation manufacturers . Alternatively non load-bearing internal walls can be founded on top of the capillary breaking layer, see figures 19 and 21 on pages 27 and 28. If bracing walls are not founded as loadbearing walls one must ensure that the vertical reaction can be absorbed by the bed on which the wall is resting (e.g. concrete slab). Workmanship Foundation work starts by excavating an area similar to the geometry of the building - for example to a level corresponding to the upper side of the deep strip foundations (see figures 6, 7 and 8). However, topsoil must be removed to a depth where the stratum is no longer weak and compressible (removal of layers containing organic material). Hereafter commences the excavation of trenches for the foundation according to dimensions (widths and depths) given in table 2. Dug out material must under no circumstances be filled back into the trenches. Notice that the foundation level (depth) shall at least correspond to the underside of the floor to be constructed later. Concrete 5 or better is used for the casting,

see paragraph on concrete. Internal wall foundations in houses with ground supported floor shall only be taken down to load bearing subsoil, as they will not be exposed to frost (due to the temperature conditions under the house). If the oversite excavation level is lower than the topside of the deep strip foundation the upper part of the foundation can be cast using formwork. Alternatively hollow blocks of concrete or clinker concrete as well as massive clinker concrete blocks may be used.. The hollow blocks are stacked on the strip foundation with tight joints and bonding. When casting no more than two courses must be cast at one time using 5 or better. The concrete is carefully compressed with immersion vibrator. Horizontal construction joints shall be placed along the centreline of the blocks. Solid clinker concrete blocks are laid with filled joints using mortar KC 20/80/550 or better according to the “Code of practice for the Structural Use of Masonry” (DS 414) . When oversite excavation reaches deep down it might be expedient to build the entire foundation of hollow blocks on top of a concrete blinding. The underside of the foundation shall be horizontal. Stepping shall be carried out as shown in figure 9. Where service lines are taken across the foundation, the foundation must be carried out according to figure 10.

Max. 0.60m

Max. Slope 1:1

Figure 9 The underside of deep strip foundations shall be horizontal and even. Stepping must have a maximum height of 0.6m. The gradient depends on the soil conditions, but cannot slope more than 1:1. 18 14

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Normal foundation depth

Figure 10. Where service lines cross the deep strip foundation, the underside of the foundations shall be at least 0.1 m deeper than the crossing line at a distance of minimum 0.6 m on either side of the line. Trenches for sewer and drain pipes which are dug parallel to the foundation must not be dug deeper than the bottom of the foundation. . Inserts or recesses To ensure the stability of the house it is often necessary to anchor the roof construction and/or the walls to the foundation. The placement of anchors must be determined prior to casting the foundation because the fixing of anchors can be done either simultaneously to casting or recesses can be made in the concrete for later fixing. The same applies to the placement of branch drains, which will be further elaborated in the chapters; “Drainage” and “ Domestic Ground supported floor”.

Concrete Concrete 5 or better is used, cf. table 3. According to” Code of Practice for the structural use of concrete” (DS 411). the crushing strength of the concrete shall be controlled but factory control is considered adequate when concrete is supplied by a concrete manufacturer being a member of the “The Concrete Manufacturers’ Control Board” (In Danish FBK) or “The Danish Concrete Certification” (In Danish DBC)

Furthermore, concrete can be mixed on site without strength control as stated in table 3. The slump range of the concrete should be between 60 and 100mm and must not exceed 150mm. The requirements for concrete aggregates and the implementation of concrete work are described more thoroughly in the ”Code of Practice for the Structural Use of Concrete” (DS 411) Concrete and light clinker concrete hollow blocks shall fulfil the requirements for strength class 3.0 Mpa and must be delivered from a factory affiliated to an approved control system (i.e. marked with a triangle). Solid clinker concrete blocks shall fulfil the requirements for strength class 2.6 MPa according to “Code of practice for the Structural Use of Masonry” (DS 414) and must be delivered from a factory affiliated to an approved control system (i.e. marked with a triangle or marked “LBK”)

Table 3. Concrete mixing ratio (cement: sand: stone) Concrete type Mixing ratio according to volume Concrete 5 1:4:7 Concrete 10 1:3:5 Concrete 15 1:2:3 Mixing ratio according to weight 1/4/6 1/3/4 1/2/2½

Note: According to new standards concerning concrete strength the values in the table are no longer applicable. When using prefabricated concrete it is recommended to prescribe concrete 4, 12 and 16 respectively

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Drainage
Houses shall be built in such a way that surface water, ground water and earth moisture do not cause damage. Hence, surface water shall be drained off by establishing an adequate slope in the ground away from the house, see figure 11. Where the subsoil is not adequately self-drained, that is where infiltration water does not quickly soak away by itself, drains shall be established along the external wall foundations of the house – a socalled perimeter drain. However, a perimeter drain can be left out in houses where the surface of the floor deck is more than 300mm above the external ground level. The purpose of draining is to reduce or completely remove water pressure on construction carried out directly against the soil. In this way seepage in the construction can be minimised and building components below ground can be kept reasonably dry. Draining does not eliminate moisture and, depending on the circumstances, draining must therefore be supplemented with moisture insulation. In this chapter only draining of houses in noncomplicated situations will be described, that is where the ground water level is below the

drainage level. In this case, drainage only includes the draining off of infiltrated surface water. Draining shall be carried out in accordance with the Code of Practice for the groundwater drainage of structures (DS 436) and Code of Practice for Sanitary Drainage - Waste-water installations (DS 432). A more comprehensive discussion on the subject can be found in SBI direction 185: Sanitary Drainage Installations. Workmanship A drain consists of two parts, namely the drainage pipe and the drainage fill. Drainage fill is a filter (for instance gravel) which ensures the collection and transportation of affluent water from the surroundings. At the same time it prevents unwanted pollution and possible blocking of the drainage pipe (in the form of sediments). Thus the filter shall be build of a material with a grain size that fulfils the so-called filter criteria (criteria that regulates the size and the grains in the filter and the grains of the surrounding soil). The drainage pipe, which usually consists of a perforated pipe (with slits and holes in the pipe wall) directs the captured water to e.g. established waste water installations. When building a filter the pore size and the flow Figure 11. Ground levelling must drain surface water away from the house. On flat terrain the slope away from the house must be minimum 20 per mill (1:50) within a distance of 3 m. On sloping terrain the ground must be levelled on the side of the house where the initial level is highest, and an intercepting drain must be installed at the intersection between the initial terrain and the levelled ground

Flat terrain

Sloping terrain

Perimeter drain

Intercepting drain

Slope

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openings should increase from the surroundings towards the drainage pipe. Drainage pipes shall be laid with a grade of at least 3 per mille. Due to the risk of frost damage the overall bottom level should be at least 0.60m below finished ground level. Moreover, the highest bottom level should be at least 0.3 m below the construction part to be drained. Excavations must not be carried out below the bottom level of the foundations. Pipe dimensions must not be less than 70 mm (as smaller dimensions may cause cleaning problems). Pipe and fittings must fulfil the requirements laid down in the Code of Practice for the groundwater drainage of structures (DS 436). Pipes without socket joints should not be used. Figures 6,7 and 8 show examples of placing a perimeter drain. If the surrounding soil consists of clay (firm cohesive soil), the filter may consist of a layer of small pebbles (2-8 mm) or pea gravel (5-16mm). A coarser material may be used when 80mm perforated PVC pipes or similar are used. In sand and similar (noncohesive soil) a filter of wellgraded sand with d10>0.3mm and 1,5mm<d50<2,5 will be suitable. In this case the slits in the drainage pipe must not exceed 1,5 mm in width. The designations d10 and d50 refer to the mesh size in a sieve through which 10 percent and 50 percent respectively of the filter material can pass. A filter shall have a thickness of at least 0.10 m at all sides of a drainage pipe. Protective wraps such as filter cloth with small pore sizes may cause clogging and as such they must not be used neither to substitute the filter nor as a supplementary filter to gravel fill. When backfilling the excavation the topmost layer must have a thickness of minimum 0.20 m and must consist of a sealing layer (for instance topsoil mixed with clay) and the ground shall be re-established sloping away from the house, as described in figure 11.

Branch drain A branch drain, connecting the capillary breaking layer to the perimeter drain, must be established below domestic ground floors and below basement floors – see figures 6 and 8. The branch drain secures the discharge of water from the capillary breaking layer and also serves as a pressure equaliser in order to prevent the radioactive gas radon from penetrating the building. At least two branch drains must be established per building. If the capillary breaking layer is divided into sections by foundations of internal walls, a branch drain must be established for each section. External basement walls Under normal circumstances external basement walls shall be drained by the use of a perimeter drain system which can capture the surface water which always seeps into the soil around a basement. The perimeter drain system shall be placed in such a way that that it can effectively drain the capillary breaking layer below the floor via a branch drain. Consequently, the bottom level in the drain pipe shall always be placed below the top level of the capillary breaking layer. There are no special requirements for the material which is used as backfill above the filter. However, along the wall a so-called wall drain must be established. This drain captures and directs surface water to the perimeter drain, see figure 8. This drain can either consist of well-drained sand or gravel with d10>0,3 mm in a thickness of at least 0.2 m or an insulating material with properties for draining. The primary function of the so-called drainage slabs (thin PVC slabs) is to insulate the wall against moisture penetration (not draining). Consequently they must always be used in combination with a wall drain (as described above). Cleaning Drains must be accessible to cleaning and consequently inspection chambers 21 17

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(manholes) and inspection junctions (the latter with a diameter of minimum 300 mm) must be established at selected bends and on level stretches at intervals not exceeding 60 m. Figure 12 shows some examples of placement of inspection junctions in a drainage system. When placing inspection junctions considerations must be given to the fact that

the tools used for cleaning may have difficulties in passing bends without the risk of damaging the pipe. As a consequence all bends must be accessible for cleaning from two sides via inspection junctions. Surface water must not be drained directly to the drainage system. It is, however, permitted to drain the insignificant amount of rainwater from light shafts or covered external basement stairways directly to a perimeter drain. It is not necessary to ventilate drainage systems. Drainage Drained water is usually discharged to a waste water installation. The connection shall be made to a 300 mm gully at least 0.2 m above the water level. The gully must have a sand trap, a gully trap and a rain water inlet. Also, the connection level must lay above the highest damming level in the main sewer system with the addition a safety factor of 0.3m. This type of “direct” connection must

Figure 12 Example of placements of inspection junctions in a drainage system.

Minimum 2 m away from non habitable buildings or basement Minimum 5 m away from habitable building or basement Filter cloth Plot boundary

Figure 13 Fascines shall be placed inside the property boundary and at least 2 m away from any boundary line. Furthermore, they shall be placed at least 25 m away from drinking water wells, inspection chambers and the like. The distance from the centre line of the fascine (longitudinal axis) and from the fascine extremities to domestic houses shall be at least 5 m. Fascines are build as 0.40.5 m wide stone-filled trenches with a horizontal bottom. Stones to be used could be 32/64 mm washed course gravel covered with filter cloth and a layer of soil of at least 0.3-0.4 m. The volume of a fascine in clay soil can be determined at 1 m3 per 30 m2 rain area. When constructing fascines of a considerable size it must be considered to establish a distribution pipe. Before connection to the fascine the rainwater shall pass a sand trap. Maintenance of fascines is the sole responsibility of the proprietor .
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only be carried out provided the whole drainage system is situated above the maximum damming level of the waste water installation in order to prevent pollution of the drainage system. In cases where these conditions can not be fulfilled the connection must be made through a pump well. When the outlet from the pump well is situated less then 0.2 m above maximum damming level it must be supplied with a retention valve.

Protection against rats In areas pestered by rats it is advisable to place a detachable grid (made from copper or galvanised steel) at pipe openings in the inspection chambers and junctions in order to avoid the penetration of rodents into the pipes. Fascines Whenever building as well as soil conditions are considered appropriate, the authorities may approve the discharge of water from roofs, smaller paved areas and drainage water directly into a fascine for percolation. For detailed design we refer to “Code of Practice for smaller drainage disposal systems for percolations into the ground” (DS 440)

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Ground supported floors
A ground supported floor is a floor construction resting directly on the ground. Ground supported floors shall be insulated against ingress of moisture and loss of heat. Also they shall be sufficiently sealed in order to prevent the ingress of air containing radon (from the subsurface). In the “Heat loss frame” (see chapter on Thermal Insulation) ground supported floors assume the U-value 0.20 and in case of floor heating 0.15. A domestic ground floor is usually constructed as follows: At the bottom a capillary breaking layer preventing the absorption of ground moisture into the floor construction. This layer is followed by a heatinsulating layer and next a so-called load distributing layer usually in the form of a concrete slab cast in situ, and finally a floor finish. When the floor finish is a joist floor, a minor part of the heat insulation can be placed on top of the concrete slab. Apart from the floor finish all materials used in the construction of the domestic ground floor must be non sensitive to moisture. An extensive treatment of questions concerning moisture in ground supported floors can be found in “SBI Directive 178 The moisture insulation of buildings”. Ground conditions Ground supported floors shall rest on a strata of subsoil which as a minimum fulfils the requirements applying to the level of oversite excavation, mentioned on p. 18. If this level is deeper than the underside of the capillary breaking layer the remaining gap must be filled with replacement material such as sand or gravel which is filled in gradually using watering and compacting (with a plate vibrator). Capillary breaking layers Capillary breaking layers may consist of : Pebbles, shingles or gravel with a minimum grain size of 4 mm; Coated, loose light clinkers (expanded fired clay) with a grain size of 10-20 mm;
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Light weight clinker floor blocks or polystyrene insulation slabs resting on a levelled gravel surface The thickness of the capillary breaking layer shall be at least 150mm. Heat insulating layers Insulating material shall be pressure-resistant and may consist of for example coated loose light clinkers, floor blocks, pressure-resistant mineral wool batts, or polystyrene slabs. Concluding: Some materials can be both capillary breaking and heat insulating. Concrete slab The slab should be cast in minimum 100 mm thickness using concrete 15 or better, see page 19. Shrinkage reinforcement should be used, for example 5 mm reinforcement mesh with 150 mm grid placed in the middle of the slab. When casting the slab the concrete must either have a plasticity which prevents it from penetrating the underlying layer, or it must be cast on top of a diffusion open underlay for example filter cloth. Immediately upon casting the concrete shall be protected against drying up by covering it with a vapour tight membrane, for example polyethylene foil. It should remain covered for app. 8 days. Floor finishes When using moisture sensitive floor finishes, such as wooden floors on joists or floating floors containing wood, a damp proof membrane must always be placed on top of the concrete slab as the slab will emit construction moisture for a considerable period of time after casting. A 0.15 mm polyethylene foil is suitable as a damp proof membrane. It must, however, be laid with an overlap of at least 200-300 mm. When using wooden floors on joists, the joists must rest on blocks preventing the rising of moisture, for example adjustable plastic wedges used in pairs of two. Part of the insulation material can be placed on top of the 24 20

concrete slab. In doing so, a softer insulation material may be used. This reduces cost and also reduces the total thickness of the ground supported floor. In order to avoid condensation on the top side of the damp proof membrane, the major part of the insulating material must be placed below the concrete slab. Radon-proofing When the atmospheric pressure decreases radon rises from the soil together with air. The pressure differences in question are up to 0.1 atmospheres and consequently the ingress of radon can only be avoided by equalising pressure in the capillary breaking layer with the outside pressure. Simultaneously to this the ground supported floor must be made as airtight as possible. The concrete slab is considered airtight but it is necessary to secure tightness along the foundation as indicated in figures 18, 19, 20 and 21. Equalising pressure of the capillary breaking layer can be achieved by the use of a branch drain connected to the perimeter drain, as described in the chapter “Drainage”. Examples of ground supported floors The figures 14, 15, 16 and 17 show examples of ground supported floor constructions. Achievement of the indicated U-values at the shown insulation thicknesses requires the establishment of an effective interruption of the cold bridge where the floor construction meets the foundation. The figures 18, 19 and 20 show examples where a heavy external wall meets the floor. In the remaining part of the foundation an insulating layer should always be inserted between the two leaves of clinker concrete. Solid clinker concrete blocks provide a considerable cold bridge – even when a vertical internal insulation is used. One should be aware that the inner leaf is not always airtight and this may result in the ingress of radon as the gas may penetrate through the insulation in the cavity. This can be avoided by the placing of a continuous layer of
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Concrete slab with wooden joist floor Wooden floor on joists. Damp proof membrane Concrete 100 mm Loose light clinkers, coated Loose light clinkers λ-class 80, 260 mm Loose light clinkers λ-class 100, 320 mm

Figure 14 Ground supported floor: Concrete slab with wooden joist floor placed on a capillary breaking and heat-insulating layer of loose light clinkers. The layer thickness required to achieve the U-value 0.20 depends on the l-class of the light clinkers.

Concrete slab with wooden joist floor Wooden floor on joists. Damp proof membrane Concrete 100 mm Pressure resistant insulation, λ-class 39, 125 mm Shingels capillary breaking layer, 150 mm

Figure 15 Ground supported floor: Concrete slab with wooden joist floor placed on a capillary breaking layer of shingles and a pressure-resistant insulating layer. A wooden floor is very sensitive to moisture and a damp proof membrane must therefore always be placed on top of the concrete slab, as the concrete emits moisture during a considerable period of time after casting. 25 21

Concrete slab with wooden joist floor Wooden floor on joists. Mineral wool , λ-class 39, 50 mm Damp proof membrane Concrete 100 mm Loose light clinkers, coated Loose light clinkers λ-class 80, 150 mm Loose light clinkers λ-class 100, 200 mm

Figure 16 Ground supported floor: Concrete slab with wooden joist floor placed on a capillary breaking and heat-insulating layer of loose light clinkers. The layer thickness required to achieve the U-value 0.20 depends on the l-class of the light clinkers A wooden floor is very sensitive to moisture and a damp proof membrane must therefore always be placed on top of the concrete slab, as the concrete emits moisture in a considerable period of time after casting. To avoid condensation on the topside of the damp proof membrane the major part of the insulation material must be placed below the concrete slab.
Concrete slab with thin floor finish Thin floor finish Concrete 100 mm Pressure resistant insulation, λ-class 39, 75 mm Loose light clinkers, coated Loose light clinkers λ-class 80, 150 mm Loose light clinkers λ-class 100, 200 mm

bitumen felt as shown in figure 19. Consequently, the constructions in figures 18 and 20 are only radon proof provided the inner leaf is adequately airtight – also where it meets the concrete slab. Figure 21 shows how a stud wall can be connected to a ground supported floor. Tightness against radon ingress requires a tight connection between concrete slab and wall, for example by the use of bitumen felt adhered to concrete slab and to internal wall surface. Alternative solutions, which differ significantly from the ones shown here can be found in SBI Directive 184 “The heat loos of buildings and U-values” The figures 18-21 show examples of the construction of load-carrying and non load-carrying internal walls on ground supported floors. Figures 19 and 21 show non load-carrying internal walls founded on the capillary breaking layer. Often it will be possible to place these directly on the concrete slab as shown in figure 20 and mentioned on page 18. Foundations shall be so constructed that no damage can occur as a result of ground moisture. This is normally secured by rendering foundation blockwork on the outside (150 mm below ground level) and plastering the uppermost 150 mm (the visible part).

Figure 17 Ground supported floor: Thin floor finish on a concrete slab placed on pressure resistant insulation and a capillary breaking layer of light clinkers. When using non moisture sensitive materials there is no need for a damp proof membrane.
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Figure 18 The cold bridge through the upper part of the foundation (a) is broken by the use of clinker concrete blocks with an insulating layer in the middle. Radon penetration is avoided by suspending bitumen felt across the edge insulation groove and bonding it to the concrete slab. In cases where the inner leaf will be treated with a surface coating making it radon tight the bitumen felt can taken up along the wall - overlapping the surface coating- and bonded to this. (shown with a dotted line). The figure also shows a load-carrying (b) and a non load-carrying internal wall (c). Bitumen felt under the internal walls is bonded to the concrete slab.

Figure 19 The cold bridge through the upper part (a) of the foundation is broken by an insulating layer between two clinker concrete blocks in the topmost course. Radon penetration is avoided by suspending bitumen felt across the edge insulation groove and bonding it to the concrete slab. The figure also shows a load-carrying (b) and a non load-carrying internal wall (c). The latter is founded directly on the capillary breaking layer, see page 18. The foundation under the load-carrying internal wall is taken to the topside of the concrete slab and the damp proof course is bonded to the concrete slab.

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Figure T1. Placing of door at the external foundation as in figure 18 (p. 27). The concrete slab in the ground supported floor must be extended and the topmost clinker block must be changed along the door opening. Sealing against radon penetration is done by the use of bitumen felt, which is extended into the door opening. Additional floor joists are added in the door opening depending on the orientation of the joists

Figure T2
Placing of door at the external foundation as in figure 19(p. 27). The concrete slab in the ground supported floor must be extended and the topmost clinker block must be changed along the door opening. Sealing against radon penetration is done by the use of bitumen felt, which is extended into the door opening.

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Figure 20 The cold bridge through the upper part of the foundation (a) is broken by the use of clinker concrete blocks with an insulating layer in the middle. A damp proof membrane on the topside protects moisture sensitive parts of the floor construction. Casting the concrete slab on top of the foundation secures against the penetration of radon along the foundation. In case the internal leaf is not radon tight , an additional layer of bitumen felt should be inserted (as indicated with a dotted line). The figure also shows a load-carrying (b) and a non load-carrying internal wall (c). The latter is founded directly on the capillary breaking layer, see page 18.

Figure 21 The cold bridge through the upper part of the foundation (a) is broken by the placing of an insulating layer inside the foundation. In this way the insulation in wall and floor is connected. Radon penetration along the foundation is avoided by bonding a strip of bitumen felt to the concrete slab and the wall. The figure also shows a load-carrying (b) and a non load-carrying internal wall (c). The latter is not always founded directly on the capillary breaking layer.
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Crawl space
The normal height for a crawl space ranges from 0,6-0,8 m. The purpose of a crawl space is to obtain a distance from the ground to the ground floor, to prevent contact with ground moisture. See figure 22. A crawl space must be protected from ground moisture and surface water. The external wall must be constructed so that it can withstand the surrounding earth pressure.

Fire demands The floor (deck) over the crawl space, because it can be used for storage, must fulfill the same fire demands for a floor over a basement (BD 60 for 1 '/4 + 2 storey houses). U-value The deck over a crawl space must fulfill the heat frame demand of U-value 0,20.

Figure 22 Crawl space deck construction can be of prefabricated light weight slab with 100 mm insulation bonded to the underside. The outside edge of the slabs by the external walls, should be insulated in between the external leca blocks, to prevent thermal loss (cold bridge). The timber floor construction over the slab must be protected from building component moisture with a 0,15 mm polythylen DPM, laid on the slab. 75 mm extra insulation is laid on the DPM to prevent condensation on the overside of the DPM.

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Figure 23 It is recommended that ventilation vents are placed every 6 meters in the external walls. Each vent must have a minimum cross area of 150 m2. The vents must be placed so that still air pockets are' prevented in the crawl space. Air vents must be placed in internal walls when necessary, to create airflow from external wall to external wall. It must be possible to inspect the full area of the crawl space by inspection hatches and openings. With regards to the inner walls stability the inspection openings must not be placed by the external walls. If the crawl space's deck is constructed in concrete or similar non-moisture sensitive material, the number of vents can be reduced by 50%, but there must be at least one vent at each corner.

Ventilation Moisture, that enters the crawl space is removed by ventilation. For size and positioning of vents see figure 23 and 24. Crawl space floor The floor in the crawl space is normally cast in 80 mm non reinforced concrete 5 or stronger. The concrete slab can rest on the ground if the top soil is removed. It is recommended to cast the concrete on a 0,15 mm polythylen sheet. Crawl space external walls Crawl space external walls can be constructed of concrete foundation blocks that are cast with concrete or of (leca) light weight concrete blocks.

The external wall can also be cast on site in form work with concrete 10 or better. The walls must have at least the same thickness of load bearing walls above. The foundation blocks must be bonded together on a strip foundation and cast together highest two courses at a time with concrete 10. Horizontal joints must be placed in the concrete in the middle of the block. Leca blocks must be bricked up with full joints, with mortar KC 20/80/550 or better. The blocks can be reinforced with 2 pieces of BI steel or 2 pieces of 6 mm tentor steel in every 1/3 horizontal joint. The reinforcement must continue along the wall and around corners. Over lapping must be a minimum of 300 mm.

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Minimum 80-100

Minimum 80-100

Figure 24 The vents in the crawl space walls must be placed 80-100 mm over the ground and end under the crawl spaces deck (under side floor). A horizontal vent channel through the external wall can cause the ground floor level to lie too high over the ground. This distance can be reduced, if the vent channel is bent down and inwards. If so the channels cross section should be increased min. 50%.

The casting of the wall should be done at one time, the concrete must be compressed carefully with vibrator. Holes and indentations must be repaired with cement mortar 1:3. To be sure of the walls stability, because of ground pressure, see max. wall size page 38. The house must also be stabilized against wind suction, with casting of anchors in the crawl space external wall or foundation, if the walls are constructedwith leca blocks. The crawl space's external walls must be moisture resistant. The walls of blocks must be rough rendered in the full height and then fine rendered on the visible part over ground level and 150 mm under ground level.

The rest of the external side of the wall mus' be coated with bitumen. The same for walls cast in concrete 10. Filling out at the external wall must not be started before the crawl spaces floor is cast and internal cross walls are constructed. If a 4 sided supported wall is implemented then the deck over the crawl space must be constructed. Internal walls Internal walls in crawl spaces are normally constructed in concrete foundation blocks, leca blocks, light weight concrete. The walls must be a minimum thickness of the load bearing walls above.

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Crawl space deck The deck (floor) over the crawl space is normally constructed with timber floor joist or prefabricated elements of leca concrete. Under wet rooms the joists are replaced with concrete slabs. Timber joists For joists dimensions, see page 41. To obtain a U-value of 0,20, the joist construction must be insulated with approx. 200 mm mineral wool. Approx. 1/3 of the insulation shall be placed under the joists to prevent moisture concentration. The insulation must be fixed carefully so that air currents do not penetrate the joints. The deck must be wind resistant so that draughts are prevented from the floor. This can be done by placing a DPM under the floor boards and fixing it at the back of the skirting board. This will also prevent radon exposure. The floor joist construction must be insulated against moisture at the walls by laying a DPC of bitumen felt between the walls and timber. The ends of the joist in the external wall and the joist sides by the external wall must be coated 2 times with timber impregnation paint. Figure 25 shows an example of a timber joist construction, and figure 26 shows an example of a concrete slab under a wet room. Figures 27 and 28 show examples of connections between joists and external walls. To limit the joists height it is normal to use a height of 150 mm as shown in figure 25. This will reduce the max span of the joists, therefore extra load bearing walls will be constructed in the crawl space. Foundations dimensions from table 2, page 17 can be reduced to the half of the given sizes though min. 0,15 m.

•Timber joists over crawl space Floor boards DPM Joists 75 x 150 mm

Mineral wool 39, 150 mm between joists Stiff, wind resistant mineralwool boards 36, 75 mm Fixed under joists U = 0,18

Figure 25 1/3 of the insulation placed under the joists. Reduce the insulation thickness between the joists to 125 mm, increases the U-value to 0,20.
Wet room with concrete slab cast in situ Floor tiles laid in mortar Concrete slab with/without heated floor

Pressure resistant insulation, 30 mm Concrete slab Insulation X-kl.36, 150 mm fixed mechanically U = 0,19

Figure 26 Crawl space deck constructed with timber joists and concrete slab under a wet room. To keep the timber joists from the wet room, they are load bearing on brick piers.

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Floor boards Timber joists Mineral wool between joists Stiff, wind resistant mineral wool Boards under joists

Heating pipes under timber joists

Figure 27 Timber joist crawl space deck. A cold bridge is avoided by placing c vertical pressure resistant insulation in the middle of the wall. Heating pipes fixed under the joists are insulated independently. DPM laid directly under floor boards prevents draughts and radon from the crawl space.

Stud frame with timber cladding Electricity pipes on the warm side of the insulation

Floor boards, DPM Timber joists Mineral wool between joists Stiff, wind resistant mineral wool under joists

Figure 28 Timber joist construction. Cold bridge between stud frame and timber joists is prevented by placing insulation vertical over the leca block. The DPM must be bonded to the internal wall cladding to prevent draughts and radon. The bottom frame of the wall must be pressure impregnated.

Ventilated crawl space

For dimension of concrete slab cast in situ, see page 42. Leca concrete deck can be developed in standard size and load bearing capacity. To obtain a U-value of 0,20 the concrete and leca concrete must be constructed with insulation, 175 - 200 mm depending on the slabs own insulation ability. With timber floor boards on battens or other sensitive floor coverings a DPM must always be laid on the overside of the concrete deck for protection against building component moisture.

In this case a layer of insulation max. 75 mm can be placed over the DPM to prevent condensation forming on the overside of the DPM. Figure 29 is an example of a leca concrete with insulation cast on the underside. Figure 30 is an example of a wet room floor construction on a leca beton slab. An example of the connection between slab and wall is shown in figure 31. The figures 32 and 33 are details of external door and slab construction.

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Leca concrete component over crawlspace Floor boards on battens. Mineral wool 39, 75 mm, DPM.

Deck component, sandwich construction 160 mm density 600 kg/m3. Mineral wool 39,100 mm. Cast on component in the factory U = 0,20

Figure 29 Crawlspace deck of leca concrete component with insulation. Only a minor part of the insulation must lay over DPM.

Figure 31 Leca concrete component deck as show in figure 22. The deck construction isplaa as low as possible in connection to the ground level, approx. 150 mm underflow level. If the level between in and out should be reduced even more, a trench could be established along the external wall.

Figure 30 Wet floor construction on leca concrete components see page 29. If an extra 50 mm insulation is fixed on the underside of the deck a U-value ofO, 18 can be obtained. Or to fulfill the heat loss frame the extra 50 mm insulation can be placed on another building component.

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Figure 32 Detail of an inward opening door with a construction as shown in figure 31. There must be a landing of steel mesh or ground raised to the same level of internal floor covering. There must be a gap between the raised earth and external wall to prevent moisture penetration. This could be achieved by placing a paving stone on its edge to hold the soil away from the external wall. The air gap should be so wide that it is possible to clean it for leafs, dirt etc. If the entrance is designed with an open porch a smaller open drain channel will be sufficient.

Figure 33 Detail of outward opening entrance door with a construction as shown in figure 31. To be sure, that the door can open in all conditions, the landing should lay a min. of 20 mm under the doors leafs under side. The difference in levels can be solved with a steel meshed ramp etc. placed between the landing and external wall.

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Basements
A basement must be insulated against heat loss, moisture and radon penetration from the ground. The basements external walls must withstand ground pressure. The deck over an unheated basement must have a U-value of 0,40 or better. Fire prevention Basements external walls, load bearing internal walls and deck must be constructed with a minimum of a BD-building component 30. In houses of 1½ or 2 floors and basement the load bearing construction must be constructed as a BD-building component 60, and a stairway from basement to ground floor must be separated from the basement or ground floor with a minimum of a BDbuilding component 60 with a BD door 30. The walls and ceilings must be constructed with a minimum of a class 2 cladding. Basement floor A basement floor is normally constructed with a concrete slab with contraction reinforcement, heat loss, insulation and a capillary breaking layer or a combined insulation and capillary breaking layer. The U-value for a basement floor is U-value 0,20. See figures 35 and 36. Radon penetration can be prevented by casting the slab floor and the external walls foundation and internal walls foundation as shown in figure 34. The concrete floor can rest on the ground _
A

Basements external walls Can be constructed of concrete or concrete foundation blocks or solid light weight concrete blocks. Or can be cast in situ with shuttering or form work with concrete 10 or stronger. They must have a minimum thickness of the wall it carries from above. See figures 34,38, 39 and 40. Foundation blocks are laid on a strip foundation in a bond and are cast out max two courses at a time with concrete 10 or stronger. Solid light weight blocks are laid with full joints with mortar KC 20/80/550 or stronger referring to masonry norm. There must be laid Bl-steel or 2 x 6mm tentor steel or similar steel with the same strength in every third horizontal joint. The reinforcement must continue along the wall and around corners. Overlapping must be a minimum of 300 mm. The casting of the wall should be done at one time, the concrete must be compressed carefully with a vibrator. Holes and indentations must be repaired with cement mortar 1:3. If the basement wall is constructed as a cavity wall, it is recommended to fix an extra row of wall ties under the deck.

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Figure 34 The section referring to low and high lying terrain. The top part of the external basement wall is constructed as an insulated cavity wall. The insulation in the cavity must overlap the external insulation with a minimum of 200 m. In this case the top part can not be counted as (with the basement deck) load bearing for ground pressure. The basement window is constructed on the outer leaf with a brick lintel and inner leaf with a prefabricated concrete beam A cold bridge is prevented with insulation.

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Concrete basement floor 100 mm concrete Plastic membrane to prevent radon 100 mm pressure resistant insulation 150 mm capillary breaking layer of gravel Pressure resistant insulation X-kl. 39 U = 0,21 Pressure resistant insulation X-kl. 36 U = 0,20

The specified external basement wall in this, chapter fulfills the fire prevention demands and radon prevention recommendations. Filling in around the basement external walls must not start before the basement floor and internal cross walls are constructed. If a 4-sided supported basement external wall is to be implemented the deck over the basement must be constructed, also before filling in. Dimension The soil pressures forces on the basements external walls, as a rule will only be supported along 3 sides, the bottom side and two vertical sides, see figure 34; A basement deck of light weight concrete with correct construction detailing together with the basement walls, for example with reinforcement to compensate for the weakened construction due to the cavity wall, can be classed as a 4-sided supported construction. Basement walls or non-reinforced concrete cast in situ (concrete norm 5.55) can be constructed in sizes given in table 4. Table 4 Maximum sizes h x I for nonreinforced concrete 10 basement walls or foundation blocks cast but with concrete 10. h and I is given in figure 37.

Figure 35 Concrete slab basement floor with separate insulation and capillary gravel layer

Concrete basement floor 100 mm concrete Plastic membrane to prevent radon 250 mm Ieca modules Wcl.80 U = 0,20

Figure 36 Concrete basement floor combined insulation and capillary layer of Ieca nodules.
Supported Wall thickness, 300 mm 3-sided 4-sided 10 m2 15 m2

t
400 mm 13,3 m2 20,0 m2

For wall thickness between 300 m and 400 m, the maximum size is calculated with interpolation between the

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38 36

Concrete external basement wall Expanded polystyrene, X-kl.39, 125 mm, with vertical drain channels and large meshed fibre sheet against the ground. 300 mm concrete.

I, .,

U = 0,28

Figure 37 For a 3-sided supported basement external walls the max area is decided with hxl where h is the height of the forces from the earth pressure and I is the distance between the cross walls, t is the walls thickness.

Figure 38 External basement wall of concrete and external insulation. Insulation with drain channels, if a non-drained insulation is implemented. The basement wall must be moisture insulated.

On 4-sided supported walls h is measured to the underside of the floor partition. Sizes of external basement walls constructed in foundation blocks are calculated as the same as non-reinforced concrete walls cast in situ with the same thickness. Sizes of external basement walls of leca blocks can be constructed with 60% of the size for non-reinforced concrete walls with the same thickness. Insulation The U-value for a external basement wall is U = 0,30. Insulation is preferred on the outside of the basement wall underground level as the wall will be warmer and dryer. Insulation material can consist of pressure resistant material e.g. mineral wool batts or polystyrene boards with drain channels clad in fibre sheeting. See figure 38 and 39. Over ground level the basement external walls are usually constructed as a cavity wall with 100 mm insulation in the cavity, the insulation is placed min. 200 mm under ground level,

Leca block basement external wall Drain fill Pressure resistant mineral wool 39. 75 mm Bitumen coating Thin cement coating Leca block 330 mm Render

U = 0,28

Figure 39 Basement external wall offoundation blocks or leca blocks with external insulation. Moisture insulation can be made with corrugated plastic sheeting with or without thermal insulation with drain channels.

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39

Concrete external basement wall Drain fill Thin cement coating Bitumen coating Render Concrete 300 mm Mineral wool 39,15 mm LWC concrete Component 75 mm Density 645 kg/m3 U = 0,29

Figure 40 External basement wall with internal thermal insulation. overlapping the external insulation, see figure 34. External basement wall with internal thermal insulation of mineral wool batts fixed mechanically and clad with light weight concrete components, see figure 40. This solution is the best considering moisture protection and internal insulation. Moisture insulation To prevent water pressure against the basement walls a wall drain must be laid either with a drain layer gravel etc., bricking up a wall of blocks (leca) on the external side of the basement wall or insulation material with properties for draining. Note that pressure resistant insulation has not this ability. There must be a connection from the wall drains to drain by the footings. A basement external wall must be constructed in such a way to prevent moisture damage by surface water the visible top part of the wall must be rendered to approx. 150 mm under ground level. Moisture penetration on the rest of the wall is prevented either with two coats of liquid bitumen or fixing thin hard plastic, corrugated sheets.

The bitumen coating must be on a plane base and protected by a thin layer of cement mortar 1:3. See figures 39 and 40 for construction with drain blocks and external thermal insulation. Moisture insulation is not necessary on concrete walls with external thermal insulation with drainage properties, see figure 38. Concrete walls of concrete 15 or better rendering is not necessary. Internal basement walls Internal basements walls can.be constructed as other internal walls. Deck over the basement The deck over the basement is normally constructed of timber joists or pre-fabricated light weight concrete components. Under wet rooms, bathrooms, toilet with floor drain the timber joist will often be replaced by a concrete slab. Timber joists A timber joist floor partition must be constructed as a minimum of a BD-building component 30 or BD-building component 60, see figures 41, 42 and 43. A timber joist floor partition can be dimensioned from table 5. The timber joists must be protected from the walls that support them by a DPC of bitumen felt. 200-250 mm of the joists ends and sides must be coated two times with a timber preservative.

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D-floor partition 30 Min. 21 mm floor boards Min. 45 x 95 mm timber joists per max. 0,6 m Min. 95 mm fixed mineral wool

BD-floor partition 60 Min. 21 mm floor board Min. 95 x 170 mm timber joists max. 0,6 m Min. 98 mm fixedmineral wool in board form with density min. 30 kg/m3

Mineral wool in this example is fixed with: 19 x 100 mm timber boards per max. 0,3 m A class 2 cladding with thickness 12 m, e.g. 13 mm plaster board

2 mm steel wire per. min. Q,3 m 1 layer of min. class 2 cladding e.g. 13 mm plaster board 1 layer of min. class 2 cladding e.g. 15 mm tongue-and-grooved timber boards

Figure 41 Example of a timber joist floor constructed as a BD-building component 30. Instead of a 21 mm floor board a 18 mm chip board or a plywood board can be used.

Figure 42 Example of a timber joist floor constructed as a BD-building component 60. Instead of a 21 mm floor board 18 mm chipboard or a plywood board can be used.

Table 5. Free span in m for floor joists partition. Joist mm 50x125 63 x 125 50x150 63 x 150 75x150 50x175 63x175 75 x 175 100x175 50x200 75 x 200 100x20 75 x 225 100x77 Jois distance in from C/C 0,3 0,4 0,5 2,60 2,35 2,20 2,85 2,55 2,35 3,15 2,85 2,65 3,40 3,10 2,85 3,60 3,25 3,05 3,70 3,35 3,10 4,00 3,60 3,35 4,25 3,85 3,55 4,60 4,20 3,90 4,25 3,85 3,55 4,85 4,40 4,10 5,35 4,85 4,50 5,45 4,95 4,60 fi.05 5.45 5.05 0,6 2,05 2,20 2,45 2,70 2,85 2,90 3,15 3,35 3,70 3,35 3,85 4,25 4,30 4.75 0,7 1,95 2,10 2,35 2,55 2,70 2,75 3,00 3,15 3,50 3,15 3,65 4,00 4,10 4.50 0,8 1,85 2,00 2,25 2,40 2,55 2,65 2,85 3,00 3,35 3,00 3,45 3,85 3,90 4,30 0,9 1,75 1,90 2,15 2,35 2,45 2,50 2,75 2,90 3,25 2,90 3,35 3,70 3,75 4,15

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BD-floor partition 60 22 mm floor chipboard 75 x 175 mm timber joists per 0,6 m 100 mm glass wool 39 in board form fixed

Table 6. Concrete slab (deck cast in situ) Largest span m 3,1 3,5 4,0 4,3 50 Thicknes Reinforceme s nt Diameter/ Meshsize
m mm

.

25 x 100 mm laths per 0,4 m Two layers of 13 mm plaster board fitted with staggered joints. Figure 43 A BD-building component 60.

0,08 0,10 0,10 0,12 0,1?

6/200 6/200 6/150 6/150 8/?00

Concrete and light weight concrete. Light weight concrete deck components are delivered as BD-building component 60 with a load bearing capacity that fulfills the demands for residential buildings. A DPM is always laid over the component, when used with a moisture sensitive floor covering for example floor boards on battens, to prevent moisture damage from the component. A concrete deck cast in situ can be dimensioned from table 6. After casting, the slab must be protected from drying out by laying a DPM over it. For example a plastic sheet for 8 days. External basement stairway The surrounding walls of an external basement stairway must have foundations to a frost free depth, which can be set to 0,60 m under the bottom landing. But always down to stable ground. The foundation can be constructed in the same way as a foundation for an external basement wall. The walls can be cast in concrete 30, moderate environments class, see concrete norm, with a thickness of 300 mm, vertical joints must be reinforced with steel reinforcement.

The table 4 values are calculated from the following _ assumptions: Passive environment class, normal safety class, relaxed control class, see concrete norm. Concrete: Minimal characteristic. Compressed strength 15 MN/m2 (concrete 15). Reinforcement: Welded reinforcement net with2minimal characteristic 0,2 tension 550 MN/m . Provided that the slab is quadratic and simply supported on all four sides and with the same reinforcement in both directions.

The stair flight and walls over the level of the basements floor must be constructed and held away from the basements walls, as in most cases the external basement wall, by the stairway will be constructed as a cavity construction. Therefore unable to absorb horizontal forces. The gap between the stair flight and basement wall is sealed with a mastic joint. Experience shows that a stair flight is best to walk on when the total of 1 going + 2 risers = approx. 630 mm. For a basement stairway the going should be between 280-300 mm and the riser 170-175 mm. The bottom slab in the stairway must be equipped with a floor drain.

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Figure 44 External basement stairway. Isometric drawing, scale 1:50. There must be a foundation constructed under the stair flights bottom step. To prevent a coldbridge the basement external cavity wall must be taken down 200 mm below the external insulations level.

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External walls
External walls include walls in facades and in gables. External walls must 1) be able to accept and transfer load, 2) fulfil the requirements for heat insulation, 3) be protected against moisture damages and 4) be fire resistant. When a building is placed in noisy areas, external walls shall furthermore fulfil requirements concerning acoustic insulation. Heat insulation The heat insulation requirements for heavy external walls and for light external walls differ. Heavy external walls are defined as walls with a mass of more than 100 kg/m2. When calculating the mass, only the part of the wall, which is placed inside any ventilated cavity, is included. Heavy external walls are typically walls where the outer leaf is a masonry wall whereas the inner leaf is either a masonry wall or a lightweight concrete element wall. In the “Heat loss frame” (see Enclosure E) heavy external walls assume the U-value 0.30. Light external walls are typically timber or metal stud walls with an external cladding of wood, steel or fibre cement panels - or with masonry outer leaf. Light external walls assume the U-value 0.20 in the “Heat loss frame”. Windows, external doors, sky lights and glass walls all assume the U-value 1.80 in the Heat loss frame and their total area must not exceed 22 per cent of the heated floor space. Fulfilment of the requirements for heat insulation is covered in detail in the chapter “Heat insulation”. Moisture conditions External walls shall be so constructed that they will not be damaged by moisture.

Further, the construction shall be so made that any ingress of water can be lead out again. The insertion of damp proof courses and damp proof membranes can ensure this. A damp proof course is a layer, which apart from hindering diffusion also secures against moisture transport via capillary rise A damp proof membrane is a layer, which apart from hindering diffusion is at the same time airtight, that is, the joints between any lengths of barrier must not permit air leakage. Diffusion is defined as “The transport of water vapour through the pores of a material”. Insulation against moisture from the foundation or from a basement wall is established by placing a bitumen felt damp proof course at least 150 mm above ground level, see figure 46. The most appropriate material is bitumen felt type PF 2000, which is polyester reinforced felt with a mass of 2000g/m2. Alternatively, type GF 2000 can be used which is a glass fibre reinforced bitumen felt. Bitumen felt is placed above all openings in the outer leaf, see figure 45. Other examples of the placement of bitumen felt are described in “Tegl 17, Moisture barrier in masonry”, MURO, 1994. In walls containing moisture sensitive materials (such as wood, steel, gypsum and the like) a ventilated cavity shall be established between the rain shield and heat insulation and the insulation shall be covered with a windproof layer. If the outer leaf is made of bricks the width of the ventilated cavity should be at least 50 mm. Furthermore, the wall shall be so constructed that any kind of condensation is avoided. This is ensured by placing a damp proof membrane of e.g. 0.15 mm polyethylene foil on the warm side of the insulation or up to 1/3 of the total layer thickness inside the insulation layer calculated from the warm side.

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½½½

150 mm

Figure 45. Bitumen felt shall be inserted above openings or connections between outer leaf and inner leaf. The felt is attached to the inner leaf. In masonry inner leafs the felt is embedded 23 courses above the insertion in the outer leaf. If brick lintels are used above the openings (see page 50), the felt shall be embedded above the last of the courses presumed to constitute part of the lintel. When the inner leaf is constructed by the use of prefabricated elements, the felt is bonded to a height of 150 mm.

Figure 46 External walls shall be secured against moisture from below. Bitumen felt is placed securing against moisture from the foundation. At ground level the felt is at the same time inserted and glued to the concrete slab to prevent air ingress (radon). Furthermore, bitumen felt is inserted with the purpose of discharging penetrated water. If the wall is particularly exposed to driving (horizontal) rain, mortar can be left out in every second head joint in the first course above the bitumen felt. The felt is fixed to the inner leaf as described in figure 45.
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Fire precautions External walls in small houses shall be made at least as BD-building component 30, and external as well as internal wall surfaces shall be made at least as class 2 covering, see Enclosure B, “Fire”. Building components shall be joined in such a way that the fire classification of the final construction is equal to or better than the classification of each component in the construction. If the house is situated closer than 2.5 m from the boundary or the middle of a path the external wall facing the boundary shall be at least BD building element 60. Also a firm connection between the external wall and the roof covering must be established. Further, the external wall facing the boundary shall be firmly connected to the final cladding on exterior walls perpendicular to the boundary. This also applies if the distance to a neighbouring house on the same plot is less than 5 m. Passage of sound When the noise level from road or rail traffic is higher than 55 dB, the roof, external walls and windows shall be constructed to ensure that the noise level inside habitable rooms does not exceed 30 dB. Information about exterior noise levels can be gathered from the local environmental authorities. If the exterior noise level does not exceed 65 dB, the requirement for normal wall and roof constructions can be fulfilled by the use of sound reducing windows with a sound insulation equalling the exterior noise level minus 30 dB. At higher noise levels acoustic insulation for external walls and roof must be considered, see SBI-Direction 172: Acoustic insulation of buildings. In Enclosure C, “Sound”, measuring methods etc. are specified. The noise insulation for a normal window with double-glazing is 25-30 dB. If the requirement for noise insulation is 35 dB or above, only windows that are classified and controlled according to DS 1084, “Sound

insulating windows – Classification”, 1979, should be used. Heavy external walls Heavy external walls are usually made as combination walls, i.e. a cavity wall where vertical load is accepted by the inner leaf while resistance to wind load is established by the inner leaf and outer leaf in combination. The outer leaf is usually a brick wall, while the inner leaf can be a brick wall, a clinker concrete wall or a cellular concrete wall. The outer and the inner leaf shall be connected by the use of wall ties in order to ensure the combined resistance to wind load. Corrosion proof wall ties shall be used e.g. stainless steel or tin bronze wire in a number equalling at least 4-6 ties per m2 wall. If 3 mm ties are used they are usually inserted at intervals of 0.4 m in every sixth course or at intervals of 0.6 m in every fourth course. If 4mm ties are used they can be inserted at intervals of 0.5m in every sixth course. The distance between ties should not exceed 0.6 m. Below the top courses two rows of ties should be inserted at intervals of 0.3 m. Furthermore an extra row of wall ties should always be placed at intervals of 0.3 m along the edge of all openings e.g. windows. Directions for the correct design and embedding of wall ties are given in Figure 47. Wall ties embedded in prefabricated elements

Figure 47. Wall ties. Directions for the correct design and embedding. Inner and outer leafs are both constructed in brickwork

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shall be straightened in such a way that they are rectilinear and parallel when embedded in the outer leaf. If wall ties are not embedded in prefabricated elements they are usually hammered into the edge of the element simultaneously to erecting the elements (this only applies to aerated concrete elements which are 600 mm wide). Combination walls with an inner leaf made out of cellular concrete or clinker concrete elements shall be dimensioned according to the “Code of practice for the Structural Use of Lightweight Concrete” (DS 420), appendix 1. Correct dimensioning usually requires engineering assistance. This also applies even when manufacturers instructions are followed. Elements shall be erected according to the instructions of the manufacturer. Bricks used in the rain screen shall be frost proof. For masonry, a mortar similar to KC 60/40/850 or better shall be used according to the “Code of practice for the Structural Use of Masonry“ (DS 414). Examples of heavy external walls In figures 48,49,50 and 51 examples are shown of heavy external walls, which at the same time fulfil the heat insulation requirements and the requirements to a BS building components 60 construction. The
Bricwork cavity wall, 350 mm Brickwork, 108 mm, possibly with ribs Mineral wool, 125 mm 108 mm brickwork, possibly with ribs 10 mm cold bridge insulation: Rib 0 4 percentage U-value: Min. wool, 39 0.28 0.33 Min. wool, 36 0.26 0.31

values indicated show the average U-values of the external walls considering the fact that the insulation thickness is reduced due to the pillars/ribs around doors and windows, see pages 51 and 52. A solid wall (without any insulation) around windows and doors will result in an unacceptable thermal bridge. The rib percentage is defined as the proportion (percentage) between the total ribbed area and the total wall area minus the area of doors and windows.

Cavity wall, brickwork and concrete, 390 mm Brickwork, 108mm (possibly with ribs) Mineral wool, 125 mm Concrete element, 150 mm Cold bridge insulation, 50 mm

Rib percentage U-value: Mineral wool, 39 Mineral wool, 36

0

4

8

0.27

0.30

0.32

0.25

0.28

0.30

Figure 49 Combination wall with brickwork in outer leaf and concrete in inner leaf.
Cavity wall, brickwork and clinker concrete, 340 mm Brickwork, 108 mm, possibly with ribs Mineral wool , 125 mm Clinker concrete element, qoo mm, density 1200 kg/m3, possibly with ribs

8 30 mm cold bridge insulation, 0.38 0.36 Rib percentage U-value: Min. wool, 39 Min. wool, 36 0 4 8

0.27 0.25

0.30 0.28

0.32 0.30

70 mm cold bridge insulation: Rib 0 4 percentage U-value: Min. wool, 39 0.28 0.28 Min. wool, 36 0.26 0.27

8

0.29 0.28

Figure 48 Combination wall with brickwork in inner and outer leaf.

Figure 50.Combination wall with brickwork in outer leaf and clinker concrete in inner leaf.

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Cavity wall, brickwork and cellular concrete, 340 mm Brickwork, 108 mm Mineral wool 125 mm Cellular concrete element, 100 mm, density 645 kg/m3, ribs. 30 mm cold bridge insulation Rib percentage U-value: Min. wool, 39 Min. wool, 36
0 0.25 0.23 4 0.26 0.25 8 0.28 0.26

Wooden stud wall with brickwork outer leaf Brickwork 108 mm Ventilated cavity Wind tight panel Studs, 50 x 95 mm per 0.6 m Noggins, 50 x 95 mm Mineral wool, 95 + 95 mm Damp proof membrane Internal cladding Mineral wool 42, U = 0.21 Mineral wool 39, U = 0.20 Mineral wool 36, U = 0.19

Figure 51 Combination wall with brickwork in outer leaf cellular concrete in inner leaf. Light external walls Light external walls are constructed with a load-bearing frame made of steel profiles or wooden studs and with a light cladding mounted on the outside or with a brickwork outer leaf. The walls shall be constructed with a ventilated cavity, a wind proof layer, insulation and a moisture barrier. The wind proof layer can be left out provided the inside part of the wall is completely airtight and provided the insulation is fitted very carefully. If not there is a risk of a considerably increased heat loss due to increased airflow through the insulation. Studs in stud walls shall be construction wood of strength class K 18 or better according to the “Code of practice for the structural use of timber” (DS 413). Studs with a dimension of 45 x 95 mm placed at 600 mm intervals can accept and transmit usually occurring loads in ground class City and in ground class Country provided the building is not more than 8 m wide and has max.1½ storey using joisting as storey partition. Alternatively 45 x 120 mm studs also placed at 600 mm intervals can be used. Examples of wooden stud walls are shown in figures 52 and 53. Stud walls with studs per 600 mm fulfil the requirements for BD - building component 30

Figure 52 Wooden stud wall with brickwork as outer leaf.

Wooden stud wall with wooden cladding. Cover boards Ventilated cavity Distance strips. Windtight panel Battens, 50 x 45 mm Studs, 50 x 95 mm Damp proof membrane Battens, 50 x 45 mm Mineral wool, 45 + 95 + 45 mm Internal cladding Mineral wool 42, U = 0.21 Mineral wool 39, U = 0.20 Mineral wool 36, U = 0.19

Figure 53 Wooden stud wall with external wood cladding. provided the cavity is filled with fixed mineral wool in batts, and provided the wall is clad with a class 2 covering of minimum 12 mm thickness. A ventilated cavity is allowed behind the external class 2 covering. The requirements for BD-building component 60 are fulfilled when the covering is replaced by two layers of 13 mm plaster board on either side or – provided rock wool

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Metal stud wall with brickwork outer leaf Brickwork, 108 mm Ventilated cavity Exterior gypsum board, 2x9 mm Steel profile studs, 150 mm per 0.6 m Gypsum board, 13 mm Damp proof membrane Z-profiles (horizontal), 50 mm per 0.6 m Mineral wool, 150 + 50 mm Gypsum board, 13 mm Mineral wool 39, U = 0.21 Mineral wool 36, U = 0.20

covering, possibly placing insulation in the cavity, as shown in figures 54 and 55. The damp proof membrane could be placed between the two layers of board. The dimensioning of steel frame walls must be done in accordance with the manufacturer’s instructions. Loads can be determined according to Enclosure A, Load. Examples of steel frame walls are shown in figures 54 and 55. Steel frame walls will usually fulfil the fire requirements. As with regard to the exact design, we refer to the manufacturer’s instructions. Other external walls Examples of other external walls are shown in figures 56, 57, 58 and 59. In cases where the wall is ventilated it is necessary to cover the insulation with a wind proof layer. When leaving out a damp proof membrane on the warm side of the construction it is recommended to use a very diffusion open material as wind proof layer. The diffusion resistance (Z-value) should be as low as 1-2 GPa s m/kg as there is a considerable risk of
Aerated concrete element with exterior wooden cladding Wooden cladding Ventilated cavity Distance strips Wind tight, diffusion open layer with a Z-value <1-2 Studs, 50 x 95 mm per 0.6 m Noggins, 50 x 95 mm Aerated concrete element, 100 mm Density 645 kg/m3 U = 0.18

Figure 54 Metal stud wall with brickwork as outer leaf.
Metal stud wall with cladding made from profiled steel plating Profiled steel plating Ventilated cavity Distance profiles External gypsum board, 2 x 9 mm Steel profile studs, 150 mm per 0.6 m Gypsum board, 13 mm Damp proof membrane Z-profiles, 75 mm per 0.6 m Mineral wool, 150 + 75 mm Gypsum board, 13 mm

Mineral wool 39, U = 0.21 Mineral wool 36, U = 0.19

Figure 55 Metal stud wall with external cladding made from profiled steel plating. is used – by two layers of class 2 covering, each layer at least 12 mm thick and the concealed layer in batt form. A ventilated cavity is allowed between the two layers of class 2 covering. In non load bearing walls (typically gable walls) it is sufficient to use one layer class 2 covering, provided rock wool is used. Steel frame walls are usually clad with plasterboard. Load carrying steel parts shall be protected against corrosion. Due to strength, fire and sound at least two layers of 13 mm plaster boards should be used as internal

Figure 56 Inner leaf made of aerated concrete with exterior wooden cladding. The density of the wall on the inner side of the ventilated cavity is less than 100 kg/ m2, consequently the wall is classified as light external wall.

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Concrete element with exterior cladding in corrugated fibre cement sheets Fibre cemet sheets Ventilated cavity Distance battens Windtight, diffusion open layer with a Z-value <1-2 Studs, 50 x 145 mm per approx. 0.6 m Mineral wool 39, 145 mm Concrete element, 120 mm

Clinker concrete element with exterior cladding in mineral wool bats. Reinforced plaster Facade batts, mineral wool 45, 150 mm Adhesive substance + fixing brackets Clinker concrete element, 100 mm, density 1200 kg/m3

U = 0.27

U = 0.27

Figure 57. Inner leaf made of concrete with exterior cladding in corrugated cement fibre sheets. The density of the wall inside the ventilated cavity is greater than 100 kg/m2, consequently the wall is classified as heavy external wall.
Clinker concrete element with exterior cladding in smooth panels Smooth cladding panels Distance strips Windtight, diffusion open layer with a Z-value <1-2 Studs, 50 x 120 mm per approx. 0.6 m Mineral wool 39, 120 mm Clinker concrete element, 100 mm, density 1200 kg/m3

Figure 59 Inner leaf made of clinker concrete with exterior cladding in plastered mineral wool batts (facade batts). The density of the wall inside the ventilated cavity is greater 100 kg/m2, consequently the wall is classified as heavy external wall. Fitting of windows and external doors Window and door lintels Window and door lintels shall be so dimensioned that they are sufficiently strong to prevent structures above the lintel from stressing the window or door. Dimensioning loads for lintels can be determined by the use of enclosure A, “Load”. With regard to brick lintels one must be aware that the beam partly consists of a prefabricated lintel partly of a number of courses of bricks. It is important not to destabilize the beam e.g. by the insertion of bitumen felt or air vents. Correct placing of bitumen felt is shown in figure 45, p. 45. Likewise in other types of lintels for instance clinker concrete beams reinforced on the lower side – part of the nonreinforced cross section will constitute a pressure zone, which must not be weakened (for instance by penetration or the insertion of other components) Joints When fixing windows and external doors the joint between the post of frame and the window reveal should always be made as a

U = 0.30

Figure 58 Inner leaf made of clinker concrete with exterior cladding made from smooth panels. The density of the wall inside the ventilated cavity is greater 100 kg/m2, consequently the wall is classified as heavy external wall. moisture accumulation if traditional bitumen felt is used (which often has a Z-value of 2030). The examples fulfil the requirements for BDbuilding component 60.

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Figure 60. A two-step seal between the post of frame and the window reveal. 1) Rain shield on the outer part of the joint, 2) Pressure equalising chamber with an outlet to the open at the bottom, 3) Caulking with mineral wool, 4) Polyethylene backing 5) Airtight sealant.

so-called two-step seal, see figures 60 and 61. The sealing principle of the two- step seal consists of placing a rain seal (rain shield) and a wind seal in two separate layers with a pressure equalising chamber and a heat insulating caulking in between. The pressure equalising chamber is connected to the outside through natural leaks in the rain shield and through openings at the bottom of the post of frame (where the post of frame joins the sill of frame). Consequently, the air pressure in the chamber will by and large be equal to the outside pressure. Using this system will prevent small amounts of rainwater, which may leak through the rain

Figure 61. Five examples of design of the twostep seal shown in figure 60. Different rain shields are used: A) Mastic seal and polyethylene backing, B) Round rubber profile, C) Multi rubber profile, D) Impregnated self expanding seal, E) Mortar joint shield along the post of frames, from being pressed further into the joint. Instead the water will seep down along the backside of the rain shield and out into the open just in front of the setback seal at the windowsill. Other examples of fixing windows in external walls are shown in figures 62,63,64 and65. The issue of fixing windows is dealt with more thoroughly in SBI-Direction 177: “Joints in Facades”.

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Head

Head

Sill

Sill

Jamb

Jamb

Figure 62 Fixing a window in a combination wall with cellular concrete inner leaf. A 108 mm wide brick lintel is used above the window on the outer leaf and a cellular concrete beam is resting on two specially made reveal elements (also cellular concrete) bonded to the inner leaf. Along jambs, sill and head thermal bridges are avoided by the insertion of expanded polystyrene or the like. Wall ties fixed along the edge of inner leaf element are embedded in every four courses in the brick outer leaf. The windows are fixed to the reveal elements by the use of angle brackets before building the outer leaf.

Figure 63 Fixing a window in a combination wall with clinker concrete inner leaf. A 108 mm wide brick lintel is used above the window. The prefabricated inner leaf (wall element) is manufactured with a window opening. The reinforced lintel above the window is an integrated part of the element. The wings around the opening are monolithic with the wall element and thus they are accurate, durable and suitable as a basis for fixing and sealing the window. Along jambs, sill and head thermal bridges are avoided by the insertion of 30 mm expanded polystyrene or the like.

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Head Head

Sill

Sill

Jamb Jamb

Figure 64. Fixing a window in a combination wall with concrete inner leaf. A 168 mm wide brick lintel is used above the window. The outer leaf wall thickness is increased to 168 mm along the jambs and the sill. This construction constitutes a solid base for the fixing and sealing of the window and also constitutes a good basis for the fixing of the windowsill. The prefabricated inner leaf (wall element) is manufactured with a window opening. The reinforced lintel above the window is an integrated part of the element. In this case a 70 mm gap is created between the inner and outer leaf along the jambs, head and sill. The gap is filled with insulation to avoid thermal bridging and is concealed by the window board and the window reveals

Figure 65. Fixing a window in an external timber stud wall with wooden cladding. The stud wall is constructed using 45 x 95 mm studs mounted with 45 x 45 mm horizontal battens on both sides. The construction is supplemented with noggins and battens around the window in order to establish a firm base for the fixing of the wind tight layer on the outside and, on the inside the fixing of a damp proof membrane between the studs; for the fixing of battens, cladding, window, window board, window reveal etc. The unbroken wooden jambs in this construction constitute a relatively insignificant thermal bridge and as such the solution can be considered satisfactory.

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Internal walls
Internal walls are usually made of bricks, blocks, prefabricated elements of lightweight concrete or as stud walls (wood or steel) clad in boards (plasterboard, plywood etc). A load bearing internal wall is a wall carrying a vertical load from other building components such as roof and storey partitions. Bracing walls are walls, which are necessary to ensure the stability of the house as described on page 13. Walls that are neither load-bearing nor bracing are called non-bearing walls. Heat insulation There are no requirements for heat insulation of internal walls between heated rooms. Internal walls facing non-heated rooms assume the U-value 0.40 in the “Heat loss frame”. Fire conditions Load bearing internal walls and columns in small houses shall be made at least as BDbuilding component 30. However, in houses with 1½ or 2 storeys and a basement, load bearing walls in the basement shall be made at least as BD-building component 60 and stairs between basement and ground floor shall be separated from basement or ground floor with walls which are at least BD-building component 60. The door in this wall shall be at least a BD-door 30. Surfaces on all walls shall be made at least as a class 2 covering, see enclosure B. Fire. A 108 mm brick wall and a 100 mm clinker concrete wall fulfil the requirements for BSbuilding component 60 for storeys heights up to 2.6 m. The construction of bearing and non-bearing wooden stud walls, fulfilling the requirements as BD-building component 30 and BDbuilding component 60, is shown in figure 66. Steel stud walls clad with at least 12 mm plasterboard usually fulfil the requirements for non-bearing BD-building component 30.

Load-bearing BDwall 30
45 x 700 mm studs per 600 mm 70 mm mineral wool, mechanically fixed with 2 mm steel wire per 300 mm. Class 2 covering, minimum 12 mm thick, for example gypsum board.

Figure 66. A wooden stud wall with 45 x 70 mm studs per 600 mm fulfils the requirements for BD-building component 30 for load bearing walls when the cavity is filled with fixed mineral wool in batts and the wall is covered with class 2 covering with a thickness of at least 12 mm. The requirements for BD-building component 60 for load-bearing walls can be fulfilled by using 45 x 95 mm studs per 600 mm clad with two layers of 13 mm plasterboard on either side. If the cavity is filled with rock wool the covering can be made of two layers of 12 mm class 2 covering on either side provided the innermost layer is a panel type cladding. If the wall is non-load-bearing it is sufficient with one layer of 12 mm class 2 covering on either side provided rock wool is used as insulation. Concerning the fixing of mineral wool and class 2 covering, see enclosure B, Fire. With regard to meeting other fire requirements we refer to the supplier’s instructions. Acoustics Within the same dwelling there are no requirements concerning sound insulation. However, noise from neighbouring rooms may cause disturbance in cases where the joints between a wall and other building components are inadequately executed. Generally speaking, increasing the mass of the wall also increases the sound insulation – in stud walls, for example, by the use of a double cladding on either side of the wall.

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Examples of sound proofing walls can be found in SBI Directive 172: “The sound proofing of buildings”. Strength properties Non-load bearing walls shall be so constructed that they can resist randomly applied forces etc. At the same time they must not be exposed to any load from a possible storey partition above. Normally, walls that solely carry the load of other walls but no load from roof or storey partitions do not present any problems concerning strength properties. However, masonry walls should be constructed as 168 mm brick walls. Bracing must be individually dimensioned and retained for example as described in enclosure D, Bracing Systems. Longitudinal walls in the ground floor of 1½ and 2 storey houses and in the basement of 1storey houses (and both carrying a storey partition) can be constructed as follows: • Element walls of 100 mm cellular concrete or clinker concrete. • 168 mm masonry • Wooden stud walls with 45 x 95 mm studs per 600 mm provided the storey partition is constructed as a timber joist floor Metal stud walls shall be individually dimensioned - loads can be determined by the use of enclosure A, “Load”. The thickness of cellular concrete walls or clinker concrete walls carrying clinker concrete floor slab panels will in most cases be determined by the necessary abutment of the floor slab panels. In basements below 1½ and 2 storey houses it is often necessary to increase the thickness of cellular concrete walls or clinker concrete walls – the carrying capacity of 168 mm masonry walls is usually adequate. The load from rafters with ceiling joists resting on longitudinal walls equals the load from a storey partition, also see enclosure A, “Load”.

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Walls between joined houses

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Roofs
In this SBI directive roofs include the entire attic consisting of the roof cover, the underlay, the load bearing construction (i.e rafters or roof elements) and the ceiling construction above the underlying storey. Included are battens, distance slats, insulation, damp proof membranes etc. Arrangement of the attic is also included when the attic is used for habitation Roofs must: 1) be able to accept and transmit load, 2) fulfil thermal insulation requirements, 3) be secured against moisture damages and 4) be fire resistant. convection all joints in the dpm must be overlapped and jammed or taped. Also, joints must be in firm connection with any dpm in the external wall or the external wall itself (when constructed without a dpm). In order to prevent damaging the dpm (for instance when doing the electrical wiring) it is recommended to place the dpm inside the insulation. When doing so, the dpm must never be placed further inside the insulation than a distance corresponding to 1/3 of the total thickness of the insulation (calculated from the warm side) Non-heated cavities in roof structures must be constructed in such a way that any construction moisture or moisture which may penetrate the roof from the outside or from below can be effectively removed. This is usually done by ventilating the constructions.

Thermal insulation
The ceiling construction and walls separating habitable space from roof space assume the Uvalue 0.15 in the “Heat loss frame”. Flat roofs and sloping walls directly against roof assume the U-value 0.20 in the “Heat loss frame”. Insulation in roof and external walls must be connected or overlapping in order to prevent cold bridges.

Fire protection
For fire protection purposes, roof coverings shall be suitably fire-resistant class T roof coverings (i.e. they must be only moderately fire spreading). Examples of this are: • Roof covering of non-combustible material for example roof tiles, fibre cement sheets and metal roofing sheets on wood or steel battens. • Bitumen felt on concrete, light weight concrete, mineral wool, plywood or tongued and grooved boards. In this case bitumen felt is understood as a roof covering made from oxidised bitumen or SBS modified bitumen In non-habitable attics the ceiling construction towards underlying rooms must, as a minimum, be carried out as a class 2 covering using class A insulation material, see enclosure B, “Fire”. When the attic is used for habitation the floor deck between the attic and the underlying rooms must be constructed as a BD-building component 30. All surfaces must be carried

Moisture conditions
Roofs must be constructed in such a way that they are adequately impermeable against ingress of snow, rain and melt-water. Also they must be constructed with sufficient pitch to secure the draining off of snow, rain and melt-water. The necessary pitch depends on the type of roof covering chosen. Flat roofs covered with bitumen felt or other roofing felt require a minimum slope of 1:40 (1.5o) Moisture from heated rooms can penetrate the roof structure either due to diffusion or due to air convection (the upward movement of hot air) through cracks and crevices. Therefore, the ceiling construction must be made adequately diffusion proof and airtight. Normally the transport of moisture is hindered by mounting a strong and durable damp proof membrane (dpm) on the warm side of the insulation. In order to avoid air
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out at least as class 2 coverings, see enclosure B, Fire. Roof coverings, underlay and battens The roof covering is defined as the uppermost layer of the roof structure. The roof covering is constructed on a substrate of for example battens, boards or plywood. Certain types of roof coverings are supplemented with a subroof. The choice of roof covering influences the design of the roof construction as different roof coverings require different substrates and different roof pitches. Also the roof coverings differ in weight.. Underlays Underlays must be able to capture any precipitation which may pass through the roof covering. Underlays may be diffusion tight or diffusion open. A diffusion tight underlay must be ventilated on the lower side. The ventilation gap – the cavity between underlay and the heat insulation - must have an average height of minimum 50 mm. When using sarking felt or soft sheeting as underlay it is necessary to plan a cavity height of minimum 70 mm as the felt and the sheeting material tend to sag slightly between the rafters. Diffusion open underlays can be placed directly against the thermal insulation material. In this case care must be taken to assure that the sloping ceiling construction is sufficiently tight against diffusion and air convection. This can be achieved by careful fixing of the dpm on the warm side of the insulation. Also the Zvalue of the underlay must be less than 3 Gpa s m2/kg. When using an underlay a distance strip of minimum 22 mm thickness must be fixed on top of the rafter (when using roof tiles it must be at least 25 mm in thickness). The distance strip serves to secure the unobstructed draining away of precipitation which may ingress as well as ventilation between underlay and battens. Distance strips must be

rectangular and pressure impregnated in quality NTR, class AB. Underlays are more thoroughly treated in various publications from “Træbranchens Oplysningsråd “(TOP) and in “BYG-ERFA”. Battens Normally battens span at least 3 roof trusses and the joints must be staggered so that no more than 1/3 of the total number of battens join on the same rafter. In order to meet the requirements concerning strength and stability it is important to use battens which fulfil the requirements for roof battens in strength class K18 according to “Structural timber - Strength classes Assignment of visual grades and species” The dimensions listed below are based on experience . The distance between the battens is the distance from mid batten to mid batten measured along the rafter. Additional information about battens is found in subsequent paragraphs. Concrete and clay roof tiles Normally roof tiles are laid using an underlay and without groundwork (cement mortar). When applying an underlay, and at minimum roof pitch of 1:2.1 (25o), all types of tiles can be used. The dimensions of the battens depend on the rafter distance. At batten distances less than or equalling 0.45 m the following dimensions can be used: • 38 x 56 mm at rafter distance up to 1.0 m • 50 x 40 mm at rafter distance up to 1.3 m

Slates Slates combined with an underlay can be used at roof pitch 1:3 (18o) and above. At roof pitch above 1:1.5 (34o) 300 x 600 mm slates can alternatively be tightened with slate putty. Slates are laid on battens, the distance of which depends on the slate size. Batten

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dimensions are similar to those used for roof tiles. Profiled roofing sheets Corrugated fibre cement sheets with or without an underlay can be used at roof pitch above 1:4 (14o). Profiled sheets of steel or aluminium – corrugated or box profiled – can be used at roof pitch above 1:2 (27o). Using sealing strips at intersections, and applying careful supervision, these sheets may be used at roof pitch down 1:3 (18o). The use of continuous sheets allows for even lower roof pitch. Profiled steel or aluminium sheets may be laid on battens with greater distances than those stated for tiles. Corrugated fibre cement sheets may without further investigation be laid with a batten or purlin distance up to 460 mm. At greater support distances safety measures must be taken against the risk of workers falling from the roof, for example by the use of furring on the underside of the purlins or the use of an underlay which is sufficiently strong to act as a safety mesh – in which case it must be documented that the underlay fulfils the safety requirements defined by MK (Danish control body for building materials). Corrugated fibre cement sheets with an MK approval can be laid with the batten distance mentioned in the approval. With a roof truss distance up to 1.0 m the following batten dimensions can be used at any roof pitch:
• • 38 x 56 mm at batten distance up to 0.55 m

covering – Specifications) “TOR-Guideline no. 24, Tagbranchens Oplysningsråd”, 1998. Roofing felt must be laid on a level substrate, for example tongued and grooved boards, plywood or pressure resistant mineral wool. Required dimensions for boards and panels are stated in table 8. Table 8. Underlay for roofing felt and similar roof coverings
Material T and G boards rough sawn T and G boards Rough sawn Plywood Plywood Plywood OSB panels OSB panels Thickness mm Span m 23 1.0 17 18 15 12 15 12.5 0.8 0.8 0.8 0.6 0.8 0.6

Note: Boards and panels are tongued and grooved. Non-rectangle boards are accepted provided tongue and groove are intact. Plywood and OSB boards requires MK approval for roof structures. Rafter and ceiling construction The load-bearing construction is usually made of wood in the form of collar beam rafters, trussed rafters or common rafters/joists . By using collar beam rafters it is possible to make use of the attic for habitation while the use of trussed rafters creates an attic with limited possibilities for use. Common joists carry the roof covering, the subroof and the ceiling construction of the rooms below. The common joists rest on the wall plate which transmits the load from the roof construction to the loadcarrying walls. The thickness of the wall plate should be minimum 38 mm. To avoid cold bridges at least one layer of the insulation should be placed on top of the tie beam. The damp proof membrane must have sufficient strength and be absolutely airtight, for example 0.15 mm polyethylene foil. Overlays should be clamped and when this is not possible the joint must be secured using an appropriate tape.

50 x 61 mm at batten distance up to 1.1 m

Roofing felt Roofing felt can be used at roof inclinations down to 1:40 (1.5o). At roof inclination above 1:5 (11o) the roof covering must be mechanically fixed in order to avoid sliding. Regarding roofing felt quality, reference is made “Tagdækning – Specifikationer” (Roof

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When the cavity between the roof cover/underlay roof and the insulation is ventilated with the purpose of hindering moisture accumulation in the roof construction, the total area of the ventilation gap must correspond to minimum 1/500 of the floor area (ground floor), and the ventilation gap must be evenly distributed along the house facade. Rafters can be produced according to TRÆ 28: “Træspærfag” (Wooden rafters), but usually prefabricated rafters produced by a factory affiliated with “Træspærkontrollen” (the “wooden rafter control board”) (TS marked) are used.

An example of insulation of wasted attic space is shown in figure 72 and an example of insulation near the collar beam is shown in figure 73. In a habitable attic the floor partition towards underlying rooms must have sufficient strength and be made at least as BD building element 30. Concerning timber joist floors reference is made to p. 41. When joists are joined along a longitudinal internal wall the joints may be carried out as described in “TRÆ 28: Træspærfag” (“WOOD 28: Wooden rafters”). Trussed rafters Trussed rafters are usually made with a roof pitch from approximately 1:4 (14o) and upwards. For repair and inspection purposes it is expedient to establish not only an access but also a duckrun in the attic. The ceiling construction may be thermally insulated as shown in figure 74. An example of a junction between an external wall and a ceiling is shown in figure 75. Common rafters/joists Common rafters/joists carry the roof covering, the subroof and the ceiling construction of the rooms below. In flat roof constructions the necessary height for placing the insulation and for establishing sufficient slope can be achieved by adding additional joist laid to fall. An example of this is shown in figure 76.

Collar beam rafters
Collar beam rafters with a roof pitch of approximately 1:1 (45o) creates an attic suitable for habitation.
Collar beam rafter Roof tiles on battens Distance strips Diffusion tight underlay roof

Ventilated cavity Rafter, 75 x 225 mm per 1.0 m Damp proof membrane Battens, 50 x 50 mm Mineral wool, cl. 39, 150 + 50 mm Ceiling cladding

U = 0.20
Figure 71. Collar beam rafter with roof tiles on battens and diffusion tight underlay roof..
Collar beam rafter Roof tiles on battens Distance strips Diffusion tight underlay roof

Noninsulated partition Collar beam rafter Battens on internal side of rafter Damp proof membrane Battens 50 x 50 mm Mineral wool, cl. 39 Ceiling cladding

Ventilation between underlay and insulation

Wooden floor,. Timber joists. Mineral wool Ceiling cladding on furring

Figure 72. The sloping roof in the wasted attic space is moisture and heat insulated in the same way as the sloping roof in the habitable part. The damp proof membrane is placed 50 mm inside the construction to avoid puncture from electrical installations. The wall separating the wasted attic space from the habitable part shall be constructed using minimum class 2 covering. The floor partition shall be BD building element 30 all. This also applies to the part of the partition in the wasted attic space where a the floor covering must be made.

Thermal insulation of attics can be carried out as shown in figure 71.
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Roof tiles on battens Distance strips Diffusion open underlay roof Collar beam rafters

Ventilated attic

Mineral wool Damp proof membrane Furring Ceiling cladding Battens on internal side of rafter Mineral wool Damp proof membrane Furring Ceiling cladding

Figure 73. Collar beam rafter with roof tiles on battens and diffusion open underlay. The sloping wall is insulated with 200 mm and the collar beam rafter ceiling with 250mm mineral wool class 39 (U-value 0.20/0.15).

Figure 74. Heat insulation against attic placed on top of the ceiling covering which again is fixed to the ceiling joists.
Trussed rafter tie beam Ventilated attic Tie beam, 50 x 150 mm per 1.0 m Mineral wool 39, 100 + 150 mm Damp proof membrane Ceiling cladding

U = 0.15

Corrugated sheets on battens Trussed rafters

Cavity wall. Brickwork and clinker concrete element

Figure 75. Trussed rafter with corrugated sheet on battens. The rafters rest on a Ventilated attic wall plate which is mechanically fixed to a light concrete inner leaf. The damp proof membrane is clamped between a ledge and the wall plate. Mounting Mineral wool on top of and between of vertical and sloping tie beams Damp proof membrane plywood windbreakers Battens prevent the wind from Mineral wool blowing directly into the Ceiling cladding insulation. Ventilation at the eave is ensured through the in figure 76. corrugation in the sheets.

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The cavity between the roof covering and insulation must have a height of at least 50 mm, and it must be ventilated through openings evenly distributed along the eaves with a total area corresponding to minimum 1/500 of the ground floor area. The use of ventilation caps is not allowed. Wooden rafters/joists can be dimensioned using table 9 – distinguishing between light and heavy roof covering.

Roofs with rafters can be heat insulated as shown in figure 76. An example of external wall and ceiling junction is shown in figure 77. Wooden roofing elements A roof may be constructed using prefabricated elements made of wood or concrete. Figure 78 shows an unventilated roof made up of wooden elements The elements span between a facade wall and a longitudinal internal wall, but it may also span between transverse wall e.g. in detached houses.

Minimum slope 1:40 Wood roofing elements Roof tiles on battens Distance strips Diffusion open underlay roof

Common joist with additional joists laid to fall Roof covering on substrate (plywood, particle board and the like) Ventilated cavity 45 x 95 mm additional joist laid to fall, minimum slope 1:40 Mineral wool 39, 200 mm Damp proof membrane Ceiling cladding on furring

U = 0.20

Mineral wool 39, 195 mm Damp proof membrane Furring, 22 x 95 mm Ceiling cladding

U = 0.18
Figure 76. Common joists with low roof pitch. Sufficient roof slope has been established by adding additional joist laid to fall. Figure 77. Common rafter with bitumen felt or roofing felt on wooden substrate. In the roof as well as in the external wall the damp proof membrane is placed 50 mm inside the construction to avoid puncture from electrical installations. The damp proof membranes in the roof and in the wall are overlapping and joined at the edge of the wall plate (clamped under a ledge). The cavity above the roof insulation must be at least 50 mm high and 10 mm above the windbreaker.

Figure 78. Wood roofing elements with roof tile covering on battens. The underlay is not ventilated.

Roofing felt Wooden substrate Ventilated cavity Common rafter

windbreaker

Wooden stud wall with weather boarding

Mineral wool between rafters Damp proof membrane Battens Mineral wool Ceiling cladding

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Table 9. Maximum horizontal span for common rafters and common joists with light and heavy roof covering.
Light roof cover
Rafter/joist distance is centre to centre

Heavy roof cover

Rafter/joist dimension w x h, mm 63x150 75x150 50x175 63x175 75x175 50x200 75x200 100x200 75x225 100x225

0.6 m 3.31 3.51 3.58 3.86 4.10 4.09 4.62 5.08 5.19 5.71

0.8 m 3.01 3.19 3.25 3.51 3.72 3.72 4.19 4.62 4.72 5.19

1.0 m 2.79 2.96 3.02 3.26 3.46 3.45 3.89 4.29. 4.38 4.82

1.2 m 2.66 2.79. 2.84 3.07 3.25 3.25 3.66 4.03 4.12 4.54

0.6 m 3.06 3.25 3.31 3.57 3.79 3.78 4.28 4.71 4.81 5.30

0.8 m 2.78 2.95 3.00 3.24 3.44 3.43. 3.89 4.28 4.37 4.81

1.0 m 2.58 2.74 2.79 3.01 3.19 3.19 3.61 3.97 4.06 4.47

1.2 m 2.43 2.62 2.62 2.83 3.01 3.00 3.40 3.74 3.82 4.20

The figures in the table have been calculated using the following criteria:: Construction timber is strength class K18 according to the Code of Practice for the Structural use of Timber. Dead load of roof covering and underlay: Light roof cover 0.25 kN/m2 (for example corrugated sheets or roofing felt), heavy roof cover 0.55 kN/m2 ( for example roof tiles). Dead load of insulation and ceiling cover: 0.25 kN/m2 (non-plastered ceilings). Dead load of rafters/joists: 0.05 kN/m2 for dimensions up to and including 50 x 200 mm, above that 0.10 kN/m2. The stated span corresponds a deflection for dead load and snow load of L/250 (L=span). Consequently the deflection for dead load alone is less than L/400 . The values in the table are applicable to flat roofs, but may be used directly for roof pitch up to 10o. At 20o roof pitch the span (measured horizontally) shall be reduced to 90%, and at 30o to 83% of the stated value. Linear interpolation is accepted.
Clinker concrete roofing elements Corrugated fibre cement boards on battens 50 x 100 mm rafters (blocked up)

U = 0.20

Mineral wool 39, 150 mm Damp proof membrane Clinker concrete roofing elements, sandwich construction, 200 mm, density of middle layer 600 kg/m3

Wooden roof elements must be produced in accordance with regulations laid down by “Tagelementkontrollen” (“The controlling board of roofing elements”) Figure 79 shows a roof made of clinker concrete elements spanning between transverse walls. When pressure resistant insulation is used the roofing felt can be placed directly on top of this. In this way the insulation is trapped between the damp proof membrane (below) and the roof cover (above). This may result in overpressure when the sun is heating the roof. The pressure is equalised by the openings along the roof edges.

Figure 79. Roofing elements of clinker concrete with roof covering of corrugated cement fibre boards on battens. The fire and sound advantages of this construction makes it attractive as a roof solution in for example terraced houses with load-bearing transverse walls.
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Gable triangles A gable triangle is the uppermost part of the gable, closing the attic. A gable triangle must be able to accept and transmit the action from

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wind load to the roof construction and to the ceiling diaphragm. Gable triangles are often made simply by cladding the gable truss with wooden boards, but masonry is also an often used solution. A brickwork gable triangle must be supported, for example by tying it to a number of studs, which at the top end are fixed to the rafter and at the bottom end fixed to the ceiling diaphragm. Roofs with trussed rafters Gable triangles can be made with a wooden cladding as shown in figure 80 where the wooden cladding is fixed to an extra rafter placed above the outer leaf. The extra rafter should be anchored to prevent wind suction from lifting the roof. This anchoring could be made by the use of trimming joists which are placed between the outermost rafters as shown in the figure. At roof pitches below 30o and in terrain classes “agricultural” and “Built-up” the bracing of a bricked gable can be made as a

timber construction, see figure 81. At roof pitch up to 40o a similar construction can be used in terrain class “built-up”, but in this case the studs must be 50 x 175 mm. Roofs with collar beam rafters When the attic is used for habitation the gable triangle is often constructed similarly to the remaining part of the gable. In this case the inner leaf is mechanically fixed to the ceiling diaphragm, as well as to the tie beam and the collar beam, see figure 82. Alternatively the cavity wall in the gable can be terminated at collar beam level and the remaining part can be constructed as shown in figure 80. In cases where the attic is not used for habitation, the entire gable triangle can be constructed as shown in figure 80, but in this case the triangle must also be mechanically fixed to the collar beam. As the collar beam supports the gable it must be braced perpendicularly to the plane of the rafter. This can be achieved either by means of the ceiling cladding or by means of a duckrun on top of the collar beams.

Cantilever Annular ring nails, anchored minimum 50 mm into the gable triangle and the rafter

Gable triangle

Gable rafter Purlin anchors 2 pcs diagonally placed

Slanted nailing 2 pcs

Trimmer joist

Figure 80 Bracing of timber clad gable triangle. In order to counter horizontal wind action the gable triangle is fixed to the battens along top edges. Likewise it is fixed to the gable truss along the bottom edge for example by the use of short pieces of batten fixed to the tie beam. When using a light roofing material it is imperative to anchor the gable triangle for example by the use of trimmings connecting the gable to the outermost trusses. The trimmings are placed close to the facades. Using distances and dimensions as stated on pages 61-62 the battens can be cantilevered up to 0.5 m.
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Legend: M 12 bolt with 30 x 30 mm washer on either side

Ø 4 mm tying wire, threaded one end for fixing in 50 x 100 mm studs placed per 600 mm in the gable trinagle. The tying wire is placed corresponding to the levels of the bed joints. After screwing the tying wire is bend 90 o upwards. Later, when the bricks are laid, the wire will be straightened and embedded in the bed joint Ø 4 mm tying wire, Z-shaped with dimensions adjusted to underlying cavity wall. One end of the tie is fixed to the top or bottom side of 50 x 100 mm noggins with 3 cramps per joint. The other end is embedded in a bed joint in the brickwork gable triangle.

Stud Noggin

Figure 81. Bracing of a brickwork gable triangle. At roof pitch up to 30o and in terrain classes built-up and agricultural the gable triangle can be braced by mechanically fixing it to 50 x 100 mm studs per 600 mm. The studs are bolted to the rafter and to the tie beam. Noggins are inserted between the studs as shown. The brickwork is braced using wire ties fixed to the studs at every fourth course. Along the topside of the gable triangle the wire ties are placed at 300 mm intervals measured horizontally in 1st and 2nd joints or in the 2nd and 3rd joints. The wall ties are fixed to the studs or to the noggins. The noggins are placed at a level corresponding to that of a brick course. In this way a wire tie can be fixed on the top side as well as on the bottom side of the noggin. Acceptable batten cantilever tolerances are stated in the text below figure 82.
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Cantilever

Annular ring nails, anchored minimum 50 mm into the rafter.

Rafter

Collar beam

Ceiling joists, braced by ceiling diaghpram

Figure 82. Bracing of gable triangle constructed as cavity wall. The inner leaf is mechanically fixed to the ceiling diaphragm, the rafter and the collar beam for example by the means of bolts. The collar beam must be braced for example by means of a duckrun or by means of panelled cladding. When a heavy roof covering is applied and at a batten distance of 0.35 m the accepted batten cantilever (calculated from the gable rafter) is maximum 0.9 m. When light roof coverings are applied using 50 x 62 mm battens per 1.1 m or 38 x 56 mm per 0.55m the accepted cantilever is maximum 0.65 m. However, the cantilever, calculated from the outer leaf, must never exceed 0.5 m. In the case of a light roof cover a cantilever of maximum 0.9 m from the gable rafter and 0.7 m from the outer leaf is accepted - provided the distance between the battens is halved within the cantilever section and the first two rafters.

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Note to Figure 81 In most circumstances, brickwork gable triangles can be constructed using less wire ties than shown in figure 81. However, gables must always be secured along all edges and when the roof construction comprises a collar tie ceiling, the gable triangles must also be secured along the collar tie. At larger gable triangles there may be a need for additional bracing and Type 1 Width Width Type 3

anchoring - for example along a vertical centre line in the gable triangle. Such bracing may be established by means of a stud anchored at ridge and ceiling level or, in case of a habitable attic space, by means of a longitudinal wall anchored firmly to the gable triangle. Figure T4 shows the principles of the mentioned bracing and anchoring possibilities. Type 2

Width

Type 4

Width

Width

Figure T4 shows the principles of the mentioned bracing and anchoring possibilities
The table below shows how wide a gable triangle may be constructed, depending on roof pitch, anchoring and terrain class. It is anticipated that the distance between the lower part of the gable triangle and collar beam is approx. 2.5 m, and also that the ridge is 8.5 m above ground level. It is further anticipated that the gable triangle is constructed as 108 mm brickwork using mortar 50/50/750. When the attic is habitable the gable triangle will normally be constructed as a combination wall. This fact is not incorporated in table T1, but the maximum widths indicated may be increased by 40 % provided the inner leaf is also constructed as 108 mm brickwork using mortar 50/50/750

Roof Pitch, degrees ≤ 30 ≤ 30 45 45 45 45

Anchoring pattern Type 1 Type 2 Type 1 Type 2 Type 3 Type 4

Built-up 13.9 19.9 9.3 > 15 > 15 > 15

Maximum width m Agricultural 11.6 16.5 7.8 12.6 10.5 > 15

Smooth 10.4 14.8 7.0 11.4 7.8 14.0

Table T1. Maximum width of a brickwork gable triangle when the triangle is secured along all three edges. The width is determined as a function of the roof pitch, anchoring pattern (according to figure 81a) and the terrain class.
Anchoring may be carried out using wire ties, which under normal circumstances will have sufficient strength when placed at 300 mm intervals. When using 3 mm stainless wire binders the space between the wall and the timber construction must be between 100 and 200 mm and using 4 mm binders the distance must be between 120 and 300 mm

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Thermal insulation
Single family houses shall be sufficiently insulated to avoid the unnecessary consumption of energy and to secure the achievement of satisfactory health conditions. The insulation qualities of the construction elements are described by their coefficients of transmission, the so-called U-values. These are calculated as described in DS 418: “Calculation of heat loss from buildings”. The U-value describes the heat loss in Watt through 1 m2 of the construction element at an outdoor/indoor temperature difference of 1 Kelvin (1K = 1oC). The U-value unit is W/m2 K and for typical constructions the U-values can be found in the previous chapters of this Direction and in “VIF, U-values’95 “. An illustration: Let us assume that a certain construction has the U-value 0.20. We increase the thickness of the insulation with 50 mm. This will result in the reduction of the U-value to approximately 0.16. Exterior construction elements, including windows and external doors, must only contain cold bridges to a limited extend. This is due to the increased risk of condensation. The energy effect of cold bridges must be taken into account when calculating the thermal transmittance (the U-value) for the various construction elements. Cold bridges may have a significant influence on the total transmission loss – even in well-insulated buildings. Consequently it is essential to analyse and calculate the effect of cold bridges. Buildings and construction elements, including windows and doors, must be so constructed that transmission loss is not considerably increased as a consequence of moisture, wind or the inadvertent passage of air. Requirements concerning cold bridges have been tightened up in Appendix 1 (By og Boligministeriet 2001) to the Building Regulations for Small Dwellings and in Appendix 4 to DS 418. Cold bridges are those parts of the building envelope which are markedly worse insulated than the rest of the envelope. They occur in ribs around the windows an along internal foundations. These cold bridges are being considered by making a calculation of an average U-value for the construction element in question. It is not new to take these cold bridges into consideration. The new thing is that it is now required to take into consideration that at corners, or where there is a change in the thickness of insulation, we find two or three dimensional effects resulting in additional heat loss. These additional thermal losses are referred to as linear loss and spot loss. The symbol for linear loss is ψ. The thermal loss through these thermal bridges is proportional to the
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length of the thermal bridge. Linear loss occurs principally along foundations and along joints around windows and doors. Spot loss occurs at metal consoles and anchors penetrating the insulation. It should be noted that the spot losses from wall ties in cavity walls has always been included in the calculation of the U-value of such a wall. Requirements to insulation in floors with floor heating have also been tightened up. Three possibilities The Building Regulations for Small Dwellings gives three possibilities for fulfilling the thermal insulation requirements for single family houses heated to at least 18oC. • Observing the U-value demands as well as the line loss demands for each construction element and at the same time reducing the total area of windows and external doors to maximum 22 percent of the building’s heated floor area. • Observing the so-called Heat Loss Frame calculated for the house with changed Uvalues for the constructions and also changing areas for windows and external doors. • Observing the so-called Energy Frame, which defines the heating requirements of the house including ventilation. In most cases the use of the Energy Frame results in the best heating economy. Also, the use of the Energy Frame gives more freedom in the choice of U-values and the choice of window and external door areas. The use of the Energy Frame, however, requires several calculations. When either the Heat Loss Frame or the Energy Frame is used to verify that the requirements for thermal insulation of a single family house are met, also the minimum requirements for thermal insulation of the individual construction element shall be observed. U-value requirements

The requirements in Building Regulations for Small Dwellings can be met by choosing construction elements with U-values lower than or equal to those listed in table 10 and at the same time ensuring that the total area of windows and external doors does not exceed 22 per cent of the total heated floor area of the house. Examples of constructions fulfilling these U-value requirements, are shown in the previous chapters.

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Table 10 Building Regulations for Small Dwellings: U-value requirements for construction elements surrounding heated rooms. ψ-value requirements acc. to DS 418
Construction element External walls with mass below 100 kg/m2 External walls with mass above100 kg/m2 and basement external walls under ground Partition walls and storey partitions adjacent to unheated rooms Ground supported floors, basement floors, storey partitions towards the outside and ventilated crawl spaces. Ground supported floors, basement floors, storey partitions towards the outside and ventilated crawl spaces with floor heating. Attic and roof constructions Including walls between attic and wasted attic space Flat roofs and sloping walls directly against roof Windows and external doors, sky lights, glass walls and hatches. U W/m2K 0.20

Table 11. Building Regulations for Small Dwellings: Requirements to minimum thermal insulation of all heated rooms. ψ-value requirements according to DS 418
Construction element External walls with mass below 100 kg/m2 External walls with mass above100 kg/m2 and basement external walls under ground Partition walls and storey partitions adjacent to unheated rooms Ground supported floors, basement floors, storey partitions towards the outside and ventilated crawl spaces irrespective of floor heating Attic and roof constructions Including walls between attic and wasted attic space Flat roofs and sloping walls directly against roof Windows and external doors, skylights, glass walls and hatches. U W/m2K 0.30

0.30 0.40

0.40 0.60

0.20

0.30

0.15

0.25 0.25 2.90 ψ W/m K 0.60

0.15 0.20 1.80 ψ W/m K 0.25

Foundations Foundations surrounding floors with floorheating 0.20 Joint between external wall and windows/ext.doors, glass walls, gates 0.03 or hatches Joint between roof construction and windows in roof or skylights 0.10 (There are no specific U-value requirements to ventilation openings, smaller than 500 cm2).

Foundations, irrespective of floor heating Joint between external wall and windows/ext.doors, glass walls, gates or hatches Joint between roof construction and windows in roof or skylights

0.10 0.30

Usually it is assumed that all rooms in single family houses are heated to a minimum of 18oC. Exempted from this rule are rooms in basement, porches and enclosed patios. When rooms are heated to temperatures between 5 and 18oC the minimum requirements concerning thermal insulation are applicable, see table 11. There are no limitations as to the areas of windows and external doors in such rooms. The heated floor area is calculated as described in the following. External walls with a mass below 100 kg/m2 are termed “light external walls”. All other walls are termed “heavy external walls”. When calculating the mass of the external walls only the part of the construction that is placed on the inside of any ventilated cavity is included. The area of windows and external doors is calculated on the basis of the dimensions of the wall openings, see figure 83.
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Figure 83. The area of windows and external doors is calculated on the basis of the dimensions of the wall opening. The dimension of the window or the door is smaller than the opening.
When calculating the area of windows and external doors only the area of windows and doors towards the outside is included. The area of windows and doors facing unheated or partially heated rooms is not included.

Heated floor area and heated footprint. When calculating the heated floor area all rooms heated to at least 18oC are included – this includes any heated basement rooms, 71

porches and enclosed patios. In Building Regulations for Small Dwellings there are no requirements for heating. Consequently it is possible to include or exclude unheated and partially heated rooms when calculating the heated floor area – provided they are thermally insulated as if they were heated rooms. The heated footprint is calculated as the projection of the heated floor area on a horizontal plane, see figure 84. The heated floor area of a building is calculated as described under “floor area” in Building Regulations for Small Dwellings, enclosure A. The heated floor area of a building shall be calculated by adding the gross areas of all heated storeys including heated basements and attics. The gross floor area shall be measured in a plane defined by the topside of the finished floor to the outer surface of the surrounding external walls. In habitable attics the area to be included shall be measured at a horizontal plane 1.5 m above the finished floor, to where the plane meets the outer surface of the roof covering. In the case of partition walls between rooms whose areas are to be included in their respective storey areas, the areas shall be measured to the middle of the wall. A room that stretches through several storeys shall only be included in the storey in which the floor of the room is situated. However, stairs and stairways are included in each storey. Heat Loss Frame. Construction elements may have a higher Uvalue then the ones stated in table 10, and the total area of windows and external doors

towards the outside may exceed 22 per cent of the heated floor area provided the total design heat loss through transmission falls within the so-called Heat Loss Frame. This means that the design heat loss (through transmission) shall be less than the heat loss from a similar reference house where the Uvalues of the construction elements fulfil requirements in table 10 and where the window and external door area constitutes 22 percent of the heated floor area. The U-values shall, however, not be higher than stated in table 11. In the subsequent paragraphs some essential extracts and rules from DS 418: “Calculation of Heat Loss from Buildings” are reproduced. The rules are used when calculating the Heat Loss Frame for single family houses.

Afootprint Figure 84. Calculating the heated footprint area

Temperatures A constant room temperature is used when calculating, usually 20oC – also in bathrooms and behind radiators. In rooms with floor heating the temperature in the floor construction is normally set at 30oC in the plane of the heating source but in principle it depends on the dimensioning of the floor heating system. The same temperature is used when determining the heat loss through foundations surrounding constructions with floor heating. It must be stressed that the temperature in the plane of the heating source is somewhat lower than the mean temperature in the supply pipes for the floor heating system. The design outside temperature is usually -12oC - also for basement walls. The design soil temperature is 10oC and is used e.g. when calculating ground supported floors and basement floors. The design temperature in ventilated crawl spaces is set at -5oC. In unheated rooms the temperature may be set by estimation or calculated by the use of the heat balance.

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Transmission areas Transmission areas for external walls, floors and roofs are determined pretending partition walls are non-existent. The transmission area for external walls is measured from the top side of the ground supported floor to the topside of the insulation in the ceiling or in the roof. In the existence of an unheated basement or a crawl space, the measurement is from the underside of the floor partition. At the corners the measurement is calculated from the external side of connecting walls. In ground supported floors the area is calculated based on internal measurements (the inside of the external wall). In ground suspended floors above basements and crawl spaces and in ceilings and roofs the transmission area is calculated based the measurements from outside wall to outside wall. When calculating unheated attics the area of the ceiling is used. Basement walls against the ground

house of reference. There must, for example, be a similar distribution of light and heavy external walls, of flat roofs, of sloping walls, of ceiling constructions against attic and of windows towards the open and towards unheated rooms. If, for instance, the Heat Loss Frame is used in order to make a window bigger then, the area of the construction element in which the window is placed shall be made equivalently smaller. Possibilities and advantages of using the Heat Loss Frame The Heat Loss Frame can, among other things, be used in order to increase the area of the windows and external doors in excess of 22 percent of the heated floor area normally accepted. Figure 85 refers to a house with light external walls and shows the relationship between the area of the windows and the external doors as a percentage of the heated floor area compared with the U-values of windows, doors and external walls. In figure 86 the same situation is shown for a house with heavy external walls. The elaboration of the graphs is based on the U-value requirements stated in the Building Regulations for Small Dwellings (indicated on the graph). The figures can be used when evaluating possibilities before calculating the Heat Loss Frame. Interpreting figure 86, for example, it is possible to deduce that the area of windows and external doors may be increased to 25 per cent of the heated floor area, provided windows and doors

Figure T4 shows the principles of the mentioned bracing and anchoring possibilities
outside ground level. Transmission areas of windows and doors are calculated on the basis of the wall openings. The length of the foundations is determined by the external perimeter. Length of joints between window/wall and door/wall is determined by the perimeter of the wall opening When calculating the heat losses it is imperative that the distribution of construction elements in the house in question corresponds to that of the U-values of windows and external doors W/m2K

.

U-values of external walls W/m2K

Figure 85. Guideline for the connection between U-values in external walls and U-values and areas of windows and external doors towards the outside in light external walls, sloping walls and in flat roofs.
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U-values of windows and external doors W/m2K

U-values of external walls W/m2K

Figure 86. Guideline for the connection between U-values in external walls and U-values and areas of windows and external doors towards the outside in heavy external walls. have a U-value of 1.6 W/m2K. When calculating the Heat Loss Frame adjoining houses are considered as one building. Use of The Heat Loss Frame must always be accompanied by matching calculations, see subsequent example. Example of Heat Loss Frame used on a singlefamily house The example is based on a 1-storey house with a floor area of 121 m2, see figure 87. Bathroom and toilet with floor heating – remaining part of the house with radiators. The external dimensions of the house are 14.4 m x 8.4 m and external walls are heavy, 350 mm thick. Internal dimensions are 13.7 m x 7.7 m (disregarding the internal walls) Based on this, the transmission area for the roof and for the ground-supported floor can be calculated to 105.5 m2. The external perimeter of the house is 2 x 14.4 m+ 8.4 m) = 45.6 m The storey height is 2.6 - measured from topside ground supported floor to topside ceiling insulation The transmission area of the vertical external planes (i.e. external walls, windows and external doors) is 45.6 m x 2.6 m = 118.6 m2. The window and external door area is 26.6 m2, corresponding to 22 percent of the heated floor area. The length of the joints around windows and external doors is 59.8 m. The house is naturally ventilated. The Heat Loss Frame of the house is 3.64 kW, see table 12. The area of windows and external

doors may be increased to 26.9 per cent of the heated floor area by choosing energy glass and thus changing the U-values to 1.6 W/m2 K, see table 13.

Table 12. The Heat Loss Frame for single family house shown in figure 87

Building component External walls Roof Ground supported floor in bathroom and toilet Ground supported floors in other rooms Windows and external doors External wall foundation in bathroom and toilet External wall foundation, other rooms Joints: Windows and doors
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Area, length m2 , m 92.0 121.0 11.7 93.8 26.6 4.1 41.5 59.8

U-, Ψ -value W/ m2 K, W/m 0.30 0.15 0.15 0.20 1.80 0.20 0.25 0.03

Temperature difference, K 32 32 20 10 32 42 32 32

Heat loss W 883 581 35 188 1532 34

332 57 Heat Loss Frame 3642

74

Facade

Bedroom

Bathroom

Bedroom

Toilet

Living room

Kitchen area

Bedroom

Figure 87. The single family house used in the example. The area of windows and external doors corresponds to 22 per cent of the heated floor area

Plan

Energy Frame The thermal insulation may also be determined on the basis of the so-called Energy Frame combined with a calculation of the total heat requirements for room heating and ventilation. The Energy Frame expresses the accepted total annual net heat requirement for heating and ventilation per m2 heated floor area

The possibilities and advantages of using the Energy Frame are described in more detail in the SBI Directive 190: “Building design and heat requirements”. The net heat requirement is the heat, which must delivered directly to rooms or to the ventilation air and does not include losses from the production of the heat in for example a boiler.

Table 13. The heat loss from the single family house shown in figure 87 with increased window area and using better insulating energy glass.
Building component External walls Roof Ground supported floor in bathroom and toilet Ground supported floors in other rooms Windows and external doors External wall foundation in bathroom and toilet External wall foundation, other rooms Joints: Windows and doors Area, length m2 , m 84.7 121.0 11.7 93.8 33.9 4.1 41.5 61.6 U-, Ψ -value W/ m2 K, W/m 0.30 0.15 0.15 0.20 1.60 0.15 0.25 0.03 Temperature difference, K 32 32 20 10 32 42 32 32 Heat loss W 813 581 35 188 1736 26 201 59 Heat loss 3639

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In the following we will simply refer to the net heat requirement as the heat requirement. Observance of the Energy Frame is done on the basis of a simplified calculation using mean values of monthly weather data. When calculating the heat requirement, factors such as insolation, heat radiation from persons and the heat accumulating capacity of the house must be taken into consideration.

Figure 14. Energy Frame for single family house with natural ventilation Number of storeys, e 1 1.7 2 Energy frame, q MJ/m2 per year 280 242 230

However, the U-values for each construction element must not be higher than stated in table 11, page 71. When calculating the Energy Frame and the heat requirement, adjoining houses are considered as one building. Calculation of the heat requirement for a single family house is described in enclosure E, Heat Requirements. According to the Building Regulations for Small Dwellings the maximum permissible heat consumption per m2 heated floor area (for heating and ventilation) in a single family house with natural ventilation must not exceed:
q r = 160 + 110 e

The Energy Frame is indicated in MJ. 1 kWh corresponds to 3,6 MJ. The Building Regulations for Small Dwellings do not require mechanical extraction. When mechanical extraction is established in kitchens, bathrooms or toilets and when the air exchange in the house exceeds 0.5-h , the Energy Frame will be increased corresponding to the increased heat requirement for heating the additional airflow, see “Energy Requirements of Buildings . Possible area of windows and external doors Using the Energy Frame it is possible to achieve bigger window and external door areas than the 22 percent of the heated floor area, which is normally accepted (when only fulfilling U-value requirements in table 10). . The figures 88 and 89 give guidance on the possible size of windows and external door area in typical detached or terraced single family houses. The possible window and external door area depends on the orientation of the windows and of the resulting reduction factor for insolation caused by shadows and also on the dimensions of the window casement, the glass type and the compactness of the building. When drawing the graphs it has been anticipated that the houses are 8 m wide, that the facades are only slightly offset, that double glazing energy glass with a U-value of 1.6 W/m2 K is being used and that the houses are constructed with heavy external walls and a pitched roof. It is further presumed that other construction elements are thermally insulated to meet to the U-value requirements as stated in table 10, page 71.

Also, the heat requirement must not exceed

q r = 280
Where qr is the Energy Frame in MJ/m2 per year and e is the number of storeys. The number of storeys is a decimal fraction, calculated as follows: e= Ae Afootprint

Where Ae is the heated floor area in m2 Afootprint is the heated footprint in m2. Concerning the calculation of heated floor area and heated footprint see page 71. The scope of the Energy Frame for single family houses with natural ventilation is indicated in table 14.
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Facades
Window and external door area in percent of heated floor area

N-S

E-W

Resulting insolation reduction factor F

Figure 88. Guiding values for possible window and external door area in typical detached 1storey house - using the Energy Frame. The graphs also apply to semidetached houses (adding up the total floor area)

Window and external door area in percent of heated floor area

Facades
1 storey

N-S
1 storey

E-W

2 storeys

2 storeys

Resulting insolation reduction factor F Figure 89. Guiding values for possible window and external door areas in a typical terraced house- using the Energy Frame.
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The reduction factor for insolation is low when the building is placed in a shady location, when windows are big and when windows are equipped with sunscreen glass. When the house is situated in a fairly open location and with normal window sizes and the use of double glazing with energy glass the reduction factor for insolation will be approximately 0.5. Reference is made to Enclosure E, “Heat Requirement”.

Similarly figure 89 shows graphs for the possible area of windows and external doors in typical terraced houses. The figure shows that the possible window and external door area also depends on the number of storeys. This applies to detached as well as semidetached single family houses. Temperature conditions during the summer period When in the design phase of a house the areas and the orientation of windows have to be determined careful consideration must be given to creating satisfactory indoor temperatures during the summer period. It must be kept in mind that drapes or blinds are not sufficient in solving the problem of insolation through large windows. The room temperature in summer can be reduced for example by constructing with a roof overhang which will shade against the sun when it is at it’s peak. Likewise, the use of heavy materials in walls and floors and the establishment of ventilation through windows that can be opened will reduce the risk of high room temperatures.

In the figures, graphs have been drawn representing windows evenly distributed towards the north and south and towards east and west respectively. In houses with a different distribution of windows, interpolation between the curves is allowed. If, for example, the windows are evenly distributed along the four main axes north, south, east and west, one can use the mean value of the curves for N-S and E-W respectively. This is also possible when for example rotating the building 45o in relation to the main axes. The window area facing south or facing southern directions may be increased without an increase of the heat requirements provided the reduction factor for insolation is greater than approximately 0.5 and provided energy glass is used. In this way it is possible to increase the window area beyond the limits of the graphs. Figure 88 shows approximation graphs which may be used as guidelines when determining the possible window and external door area in detached 1-storey houses of 120 m2 and 160 m2 respectively. Interpreting the graph, it is evident that the possible window and external door area increases proportionally to increased floor area. It is, for example, possible to obtain a larger window and external door area in 1 semidetached house of 160 m2 than in 2 detached houses of 80 m2 each. In a 120m2 house where the windows are evenly distributed on all facades (north, south, east and west) and with a reduction factor for insolation of 0.45 the guidelines will give a window and external door area of ½ x (26 percent + 38 percent) = 32 percent of the heated floor area
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Wet rooms
Wet rooms are defined as bathrooms and toilets with a floor drain and other rooms such as sculleries and laundries which are similarly exposed to water. This section covers requirements to the construction of floors and walls in wet rooms. Construction principles and the choice of materials greatly influence the installations. Requirements in this respect will also be covered, but the planning and execution of installation work is not covered. . Wet rooms are also dealt with in By and Byg Direction 200: “Wet Rooms” and in SBI Direction 180: “Bath rooms” Requirements to wet rooms The Building Regulations for Small Dwellings define the overall requirements to wet rooms concerning water tightness, stability etc. Noncompliance with requirements may have serious consequences such as material deterioration and costly repairs. Floors and walls including joints, connections and pipe penetrations must be water tight. This requirement is particularly important when a construction contains wood or other organic materials, which must be secured against the ingress of water. Constructions in wet rooms shall be able to withstand normal mechanical actions (cleaning etc) without significant deformations, i.e. tile clad walls or a watertight covering must not be damaged by such actions. Tile clad constructions in particular require a rigid underlay to prevent them from cracking. Wet rooms shall be able to withstand the exposure to hot and cold water and the constructions must not be damaged by deformations as a consequence of change in the relative air moisture content for example caused by seasonal variations. Floor and wall surfaces shall be able to withstand action caused by the use of normal chemicals used in the household and they must be easy to clean.

Wet rooms shall be designed keeping in mind that vulnerable components must be protected against exposure to water and also, to the widest possible extent, keeping in mind that surrounding constructions are not being damaged by the ingress of water Zoning A clear distinction shall be made between wet zone and moist zone, see figures 90, 91, 92 and 93. The wet zone is the part of the room frequently exposed to water. Requirements to constructions, materials and surface treatment are most rigorous in this zone. The wet zone encompasses the entire floor, the lower 100 mm of all walls, including walls in the shower area, along the bat tub and under wash basins equipped with a shower fitting. The use of fixed shower enclosures will demarcate the wet zone on the walls, see figure 91. The moist zone is the wall area outside the wet zone. This area is considered more exposed to moisture than similar areas in other rooms in the house for example caused by high relative air moisture content and the occasional exposure to water. For that reason requirements to choice of materials and constructions are tightened in this zone. Floor slope The areas of the floor directly exposed to water must slope towards a drain and the floor must be without cavities. Such areas are shown in figures 90, 91 and 93 (hatched). The slope should be 1-2 percent. However, below freestanding bathtubs and fixed furniture it must be at least 2 percent. Other areas may be constructed horizontally. A slight slope towards the drain is preferred in order to avoid the risk of back slope and cavities If a part of the floor is constructed horizontally the water from bathing must be prevented from entering into this part of the floor, for example by lowering (recessing the floor) or delimiting the floor in the shower area with a shower curb. A 10 mm recess will

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Wet zone Wet zone Moist zone Moist zone Moist zone Moist zone

Minimum width 250 mm

100 100 Wet zone Dimensions in mm Wet zone

Figure 90: Wet zone and moist zone in wet rooms with shower stall. The wet zone includes floor and wall areas within the stall area plus an additional 500 mm zone. The wet zone on the walls reaches the ceiling. In rooms with an extraordinary room height, the area above normal room height may be considered a moist zone. The hatched area shows the part of the floor where a slope is required. No pipes must penetrate the floor in this area. The area stretches 500 mm outside the limit of the stall. usually be adequate. A recess is preferable to a curb as water on the floor outside the shower area e.g. from washing the floor will be able to run into the drain. At the same time the room is better suited for wheelchair access. The recessed area should be sufficiently big to allow water from a shower curtain to drip off inside the recess. Waterproofing The application of a waterproof cladding or a waterproof surface treatment may be necessary in order to secure water tightness of floors and walls The use of a water repellent surface treatment or cladding on top of non-

Figure 91: Fixed shower enclosures: When enclosures have a minimum width of 250 mm only the part of the wall inside the stall is considered a wet zone. Pipes may penetrate the floor immediately outside the stall area provided the floor inside the stall is recessed or provided with a curb. organic materials such as concrete, light weight concrete and brick work has until recently been considered adequate wet rooms solutions. However, some of the non-organic materials such as light weight concrete and brick work are rather water absorbent and others may have leaky joints between elements. Consequently, such materials should have a water-proof surface treatment when used in areas exposed to water. It should be noted that a normal tile cladding is not considered water proof and therefore must be supplemented with water tight treatment before fixing tiles. Stud walls as well as walls and floors containing organic materials must be supplied with a waterproof surface treatment. In the wet zone the treatment shall be carried out by

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Wet zone Moist zone Moist zone

layers using one layer from one system and another
Moist zone

Wet zone

100 100 Wet zone Dimensions in mm Wet zone

Figure 92: Wet zone and moist zone in a wet room with a bathtub. The wet zone includes floor and wall areas inside the indicated zone (500 mm away form the bathtub). The wet zone on the walls reaches the ceiling. In rooms with an extraordinary room height, the area above normal room height may be considered a moist zone. Pipe penetration is not allowed inside the area marked with a dotted line (closer to the bathtub than 500 mm). Where fixed enclosures with a minimum width of 250 mm are used only the part of the wall inside the enclosure is considered a wet zone and pipes may penetrate the floor in the area immediately outside the enclosure. the use of a suitable PVC membranes or MK∗ approved waterproofing systems. An MK approved watertight tile cladding contains a watertight layer with a minimum thickness of 1 mm. Separately approved systems must not be mixed, i.e. it is not allowed to combine

Figure 93: The wall behind a washbasin is considered a wet zone only in cases where the hand washbasin is provided with a shower fitting. In this case the wet zone begins at floor level and continues to a level 500 mm above the washbasin and reaches 500 mm to either side of the basin. In cases where a shower fitting is provided also a floor drain must be established and the floor must slope towards the drain inside the hatched area. Pipes must not penetrate the floor in this area, which stretches 500 mm away from the floor drain. In case the shower fitting on the washbasin is the only shower facility in the bathroom the regulations concerning shower stalls are applicable (as described above). layer from a different system in the same construction. Also, only the types of underlay listed in the certificate of approval must be used. Further information on MK approvals may be obtained from ETA-Denmark a/s Tightening of stud walls in the moist zone may be carried out using a watertight sealant without a membrane or using a paint treatment. However, any materials used must comply with the demands stipulated in MK-

∗

MK refers to the Danish Building Material Control Board
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testing and approval conditions concerning wall claddings in wet rooms (1996). MK approval does not apply to sealant systems and paints used in the moist zone but it is possible to obtain an approval. The various possibilities of fulfilling the requirements for water proofing in wet zones and moist zones in floors and walls are thoroughly treated in the following. Water running down the walls must be led to the floor surface. Consequently, the joint between the wall and the floor must be established using a watertight seal, or the watertight layer on the wall must overlap the floor curb. When using doorframes with a threshold, the distance between floor surface and the lower level of the threshold must be min. 20 mm. In this way the floor will be able to contain a certain amount of water, for example originating from a leaking water installation. Alternative solutions must be sought when the bathroom is arranged with regard for physically handicapped. Water and drain installations Pipe penetrations should be as short and simple as possible. Joints in water pipes or joints between pipes and fittings must not be inaccessible for repair and maintenance. However, pipe installations with concealed joints may be used in “pipe in pipe systems” where any leak would be disclosed without damaging effects. Penetrations for water and drainpipes shall be carried out using watertight bushes. Penetrations in the floor should be avoided but may be carried out in areas where daily exposure to water is not expected, see figures 91, 92 and 93. It is preferable to place installations inside shafts or ducts. When bathrooms are placed adjacent to sculleries it will often be convenient to run pipes along the scullery wall facing the bathroom. Pipe installations in adjoining houses must be separate due to noise. Floor drains must be VA∗-approved according to the floor construction and floor covering in question. Whenever possible the discharge should be vertical. Floors Heavy floor constructions Heavy floor constructions consist of in situ cast concrete slab or a slab made from prefab light weight clinker concrete elements. In most cases an

additional concrete slab is cast on top of the first slab – as shown in figures 94 and 95. The two slaps are separated either by a sliding layer consisting of a double 0.15 mm PE-foil or separated by an insulating layer. The concrete must be stiff plastic, type pea gravel or pebble, 20 Mpa, and it must be at least 60 mm thick. A reinforcement of 6 mm round steel is laid in a grid with 150 mm grid distance. Alternatively a similar reinforcement mesh may be used. Additives

Figure 94: Bath room above crawl space. The floor is made of lightweight concrete elements on top of which a 30 mm hard insulation is placed. A concrete slab is cast on top of the insulation. Floor slope is established in the screed. In the wet zone floor and walls have been waterproofed using a membrane. The membrane in the floor is type PVC whereas the wall membrane is the liquid type. The joint between the floor and wall membranes has been established using an adhesive overlap joint where the wall membrane overlaps the floor membrane. The joint is reinforced using a strip of reinforced fibre. The floor membrane is fixed to the floor drain using a clamping ring. Tiles are glued with plastic tile glue.

with the purpose of increasing impermeability should be used and the concrete must be vibrated. Slopes can be established directly in the concrete slab or in a 10-40 mm cement mortar screed (C100/400). As concrete creeps and shrinks during curing the tiles must be laid as late as possible in

∗

VA is a Danish certification system for Water and Sewer installations

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the building process. The concrete must cure at least for 2-3 weeks at 20 oC . In order to compensate for additional contraction in the concrete it is advisable to use a tile glue with plastic properties. The best curing method is to cover the concrete with a polyethylene foil or similar during the first few days after casting. Normally, the execution of concrete work as

Tightness between floor and wall can be secured by covering the joint with a flashing for example using a fibre reinforced membrane as shown in figure 26, page 32 and in figure 30, page 34. When the wall is waterproofed using a membrane the flashing is created by leading the wall membrane all the way down and taking it 100 mm into the floor area. When membranes are placed in both floor and wall the two membranes must be long term compatible and the joint between them must be sealed. Light floor constructions Light floor constructions built as a timber joist floor shall, in wet rooms, have a substrate floor made out of flooring panels. This type of floor construction is moisture sensitive and an effective moisture protection must be established. The construction must not be used on ground supported floors or above crawl spaces with a height less than 600 mm. Where tiles are used as floor covering, the substrate must be made from minimum 19 mm construction plywood supported per maximum 300 mm. The panel is covered with a watertight layer, for example EPDM roofing felt or an MK approved watertight tile cladding. Floor slope can be established either by the use of wedges under the plywood or by applying a screed on top of the plywood and the watertight layer. The optimal thickness for a screed of this type is 10-30 mm using a rapid curing special cement mortar which has little shrinkage and may be clad with tiles within 24 hours after casting. When a PVC floor covering is used the substrate may be established by the use of construction plywood or particle board for flooring. Thickness and support distances may be found in “B&B direction 200 - Wet rooms”, p. 27. Floor slope is usually established by the use wedge shaped joists. The flooring panels are glued and screwed to the joists. The PVC covering is glued directly to the flooring panels and all joints are welded. PVC floor coverings shall only be carried out by professional floor fitters holding a welding certificate certifying that they have participated in and passed a test in the execution of wet rooms with PVC coverings. It must be certified that the materials used live up to the material requirements stated in B&B Direction 200. Floor membranes or coverings shall be taken up the wall and form a watertight joint with the wall

Figure 95: Bath room on storey partition facing neighbouring house. In order to reduce noise an insulating layer has been established. In this case by using two layers of 4 mm polypropylene web between pre cast floor slab and top slap. The insulating layer continues along the sides of the top slab. The floor drain is recessed into the concrete flooring element and a slope is established in the screed. In the wet zone, floor and walls have been waterproofed using a liquid type membrane. On the floor and up to a 100 mm level along the walls the membrane is reinforced and it has been taken across the flange of the floor drain to which it must be adhered. The tiles are glued on top of the water proof membrane using plastic tile glue.

described above is considered sufficient to secure water tightness. As an extra precaution it is advisable to apply an additional watertight membrane especially in the zones around the bathtub and in the shower stall. This may be done using a membrane applied in liquid form.

membrane or covering. Alternatively the wall

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membrane or covering may overlap the floor covering (on the wall). Walls Heavy walls Most often heavy walls are made from concrete/lightweight concrete wall elements or brickwork masonry. The commonly used types of concrete are normally considered watertight as such. When using brickwork masonry and lightweight concrete, moisture may be transported to adjoining rooms or building components (for example a joist floor) when the walls are exposed to water. Waterproofing is therefore recommended in the wet zones before tiling. An MK-approved waterproof tile cladding system for gypsum boards may be used for this purpose. However, attention must be paid to the fact that the function criteria may be different when applied on other materials than gypsum board. The project manager must ensure compatibility of the materials chosen. As concrete and lightweight concrete may shrink during the curing process tiles should be fixed as late as possible in the building process – ensuring that the major part of shrinkage has already occurred. As a guideline the below listed curing periods before tile fixing are recommended. When using concrete a curing period of 2-3 months is necessary depending on thickness, temperature and moisture conditions. When using light clinker concrete, fixing should only take place when the moisture content has dropped below 4-8 % (weight), depending on concrete density. The drying out will, depending on the methods applied, normally takes between 3 weeks and 2 months in a closed heated house. The remaining moisture content should always be determined before commencing tile fixing. Information concerning the drying out pattern as well as the measuring of remaining moisture content is available from the suppliers of lightweight clinker concrete.

When using aerated concrete, the drying out will take approximately 3 weeks in a closed and heated house. The use of tile glues with plastic properties is recommended when fixing tiles on concrete or light weight concrete. In this way minor movements as a result of final shrinkage, moisture and heat impact may be absorbed. Light walls Light wall are stud walls clad with gypsum board, calcium silicate board, particle board or plywood. Light walls shall be protected using a watertight layer as described in detail in B&B Direction 200. Gypsum board (plasterboard) walls can be constructed using normal plasterboards or fibre reinforced plasterboards. Plasterboards must be classified as “wet room boards” or the core must be impregnated with silicone. The entire room must be clad with boards in 2 layers on top of 70 mm deep studs placed at maximum 450 mm c/c. More detailed information on the construction of walls in wet rooms using plasterboard-clad constructions may be found in the guidelines issued by the plasterboard manufacturers. On top of steel studs and wooden studs it is allowed to use15 mm fibre reinforced gypsum board in a single layer. Plasterboards shall have a waterproof covering on the side facing the wet room. In the wet zone only the use of PVC covering or an MKapproved tile system with a watertight membrane is allowed. In the moist zones it is also allowed to use a paint treatment or a tile cladding using waterproof compounds - with or without membrane - but complying with the before said approval conditions. Calcium silicate boards may be used on top of steel or wooden studs fixed on a furring or a substrate of gypsum board or calcium silicate board. Normally such constructions are carried out using a polyethylene foil immediately below the utmost board layer. Waterproofing may, however, also be carried out applying the same principles as those used for plasterboards clad with PVC or with a

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watertight tile cladding. In this case the tile cladding must be approved for the use on calcium silicate boards. Chip boards (particle boards) and plywood may be used in one layer only with a minimum thickness of 22mm and 15mm respectively. As waterproof cladding it is only allowed to use PVC membranes with welded joints. In external walls, constructed as stud walls a damp proof membrane is usually placed between studs and the internal cladding. The waterproof cladding used in wet rooms is usually considered sufficiently diffusion tight to act as damp proof membrane. In such cases the usual damp proof membrane shall be left out in order to avoid the accumulation of moisture between two tight layers.

Ceilings Ceilings shall be constructed in such a way that moist air cannot penetrate adjoining building components or rooms. Special precautions must be taken to prevent a flow of warm and moist room air through cracks and crevices in the ceiling. Consequently, the ceiling shall consist of an airtight construction for example by using a diffusion tight panel as ceiling cladding combined with an elastic mastic joint between ceiling and wall. Alternatively the ceiling may be constructed using a damp proof membrane. Considering diffusion, it is normally only required to use a damp proof membrane when the wet room is facing unheated rooms, for example a non-habitable attic. There are no specific requirements to the surface treatment of ceilings in wet rooms but it is an advantage if the treatment can stand up to a moderate exposure of water. Joints Elastic joints are used to absorb movements between building components. In order to secure a long life span, elastic joints must be designed with geometry – sufficient width and

depth – securing the absorption of movements. It is recommended using a back up material or a slip tape to counter the mastic and a primer must be used to secure bonding on the contact surfaces. Joints must be designed in such a way that they can be replaced, i.e. cutting away existing mastic and cleaning contact surfaces. Elastic mastic for wet rooms must contain an additive of fungicide in order to avoid growth of fungi. The watertightness of a wet room must never depend on an elastic joint. “Flexible” mortar joints, i.e. cement based mortars with a plastic additive resulting in a more flexible final joint may, under certain circumstances, be used as an alternative to flexible mastic joints. “Flexible” mortar joints can only absorb small movements. Consequently, it is only recommended to use this type of joint in areas where no movements are foreseen, for example in the corner joint next to a cast curb.

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Glas Sorry - this chapter is not yet available in the English version

SBI Direction 189 KLJ Translation KLJ
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Indoor climate
In the Building Regulations for Small Dwellings indoor climate is approached as an integral part of the construction of the building, i.e. the indoor climate is seen as a result of the ventilation systems applied, the production of moisture and the emission of contaminants. In general, the Building Regulations for Small Dwellings require that single-family houses shall be so constructed that a satisfactory indoor climate with regards to health and safety can be maintained during normal use. Satisfactory indoor climate also includes such issues as comfort and well-being. In this chapter only ventilation and the emission of contaminants from building materials are dealt with. Other issues such like sound and heating are treated in different chapters of this book. A comprehensive discussion of indoor climate in buildings can be found in SBIDirective 182: The indoor climate handbook. Ventilation The purpose of ventilation is to fulfil the needs for hygiene and comfort by supplying air of an acceptable quality and to control the moisture conditions in the rooms. At the same time the ventilation system must contribute to maintaining an acceptable room temperature at a reasonable cost. Basically, ventilation shall be so designed that indoor air is being removed from rooms loaded with moisture or stale air such as kitchens, bathrooms and toilets, and outdoor air is supplied to habitable rooms. Overall, the Building Regulations require that the air change in any habitable room and the house as a whole is minimum 0.5 per hour. At a room height of 2.3 m this air change corresponds to an inflow of outdoor air of 0,32 l/s per m2 net floor area.

Ventilation principles The air change can be produced either by natural ventilation or by mechanical ventilation. Natural ventilation In a natural ventilation system the indoor air is removed through ventilation ducts in kitchen, bathroom and toilet while the outdoor air enters habitable rooms for example through hinged windows or through outdoor air inlets, see figure 99. The predominant force in a natural ventilation system is air exchange caused by thermal buoyancy, the so-called chimney effect. The chimney effect occurs when cool air enters a house on the first floor or in the basement, absorbs heat in the room, rises, and exits through upstairs windows or ventilation ducts. This creates a partial vacuum, which pulls more air in through lower-level windows. The driving forces from wind action are caused by overpressure on walls facing the windward side and vacuum on walls on the leeward side. Suction also occurs on large sections of the roof.
Removal of indoor air

Ventilation duct

Supply of outdoor air Kitchen, bath, WC

Transfer of air Habitable rooms

Figure 99; Natural ventilation. Indoor air is removed through ventilation ducts in kitchen, bathroom and toilet while habitable rooms are supplied with outdoor air.

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Mechanical ventilation Mechanical ventilation is created by the force of electric-powered ventilators. The ventilation system may be comprised of an exhaust system only or may be comprised of more advanced systems including controlled supply as well as controlled exhaust. Mechanical exhaust systems provide a higher working pressure compared to natural ventilation systems and are consequently less sensitive to variations in the outdoor climate. A ventilation system comprising both mechanical supply and exhaust is normally termed a balanced ventilation system. The ventilation system is often designed in such a way that the volume of exhaust air is slightly higher than that of the supply air. The purpose of this is to create a slight vacuum in the house and thereby reducing the risk of moisture damages to the building structures .

External wall

Figure 100. The living zone is that part of a room where the occupants usually sit or work. The figure shows a room with one external wall and three internal walls. rooms containing moisture saturated and polluted air. According to the Building Regulations for Small Dwellings, the requirements concerning the volume of the air change are considered met when rooms are ventilated as described in the following and according to figure 101. As an alternative the Building Regulations for Small Dwellings do accept that the cross sectional areas of fresh air vents are determined on the basis of professional calculations. The calculations must include such information as the design basis, the functional description and the performance data for the chosen products. Habitable rooms In habitable rooms the supply of outdoor air must always be possible through openings directly to the outside. In addition to this fresh air may be supplied by air injection. There are no requirements to exhaust. Fresh air vents are always installed in exterior walls irrespective of ventilation being supplied by natural ventilation or by mechanical exhaust. Fresh air vents are adjustable openings in the building envelope

Functional requirements in general The ventilation system must be effective around the clock – also when the occupants are absent. The reason why is that there may be a need to ventilate contaminants and moisture which do not necessarily originate from persons and which do not necessarily stop when the dwelling is vacated. The ventilation system must not cause air velocities in living zones exceeding 0.15 m/s. Velocities above this limit are considered uncomfortable as they may result in a feeling of draught. However, draught problems are not only caused by the air speed but also by the air temperature The living zone is that part of a room where the occupants usually sit or work. In general, the extremities of the living zone are defined by a horizontal plane 1.8 m above floor level and a vertical plane 0.2 m away from any exterior wall, see figure 100. The transfer of air from one room to another shall be in the direction from less polluted rooms to more polluted rooms. In a dwelling kitchen, bathrooms and toilets are considered

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Supply of fresh air
Habitable rooms

Removal of indoor air Habitable rooms

Hinged window or Hatch or External door and Natural ventilation: Fresh air vents with a cross sectional area of 60 cm2 per 25 m2 floor area or Mechanical ventilation: Fresh air vents with a cross sectional area of 30 cm2 per 25 m2 floor area
Kitchen

No demand concerning extraction

connecting a room to the outside. Figure 102 shows an example. When using natural ventilation one or more fresh air vents with a total cross sectional area of minimum 60 cm2 are required up to 25 m2 floor area and, when using mechanical ventilation, one or more valves with a total cross sectional area of at least 30 cm2 up to 25 m2 floor area. In rooms larger than 25 m2 the requirement can be met by increasing the cross sectional area with 2.4 and 1.2 cm2 respectively per sq.m. floor area in excess of 25 m2, see figure 103.

100 cm2 opening from access room
Also recommended 1.

Kitchen Natural ventilation: Ventilation duct with cross sectional area of 200 cm2 or Mechanical ventilation: Volume flow rate 20 l/s and Hood with mechanical extraction to the outside

Hinged window or Hatch or External door or Fresh air vent with a cross sectional area of 30 cm2
Bathrooms

Bathrooms

100 cm2 opening from access room Also recommended 1. Hinged window or Hatch or Fresh air vent with a cross sectional area of 100 cm2
WC and scullery

Natural ventilation: Ventilation duct with cross sectional area of 200 cm2 or Mechanical ventilation: Volume flow rate 15 l/s

Figure 102. Example of a fresh air vent, a so-called dish valve.

Natural ventilation WC and scullery Total cross sectional area, cm2

100 cm2 opening from Natural ventilation: access room Ventilation duct with cross sectional area of 200 cm2 Also recommended 1. Hinged window or or Mechanical ventilation: Volume flow rate 10 l/s Hatch or Fresh air vent with a cross sectional area of 50 cm2 1. When at least one of the surrounding walls is an exterior wall

Mechanical ventilation

Figure 101. Requirements on the supply of fresh air and the removal of indoor air.. Basements must also be ventilated.
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Floor area, m2

Figure 103. Cross sectional area of fresh air vents in habitable rooms in relation to floor area. 91

Kitchen, bathroom and toilet Kitchens, bathrooms and toilets are the rooms in the dwelling contaminated by moisture saturated and polluted air. Indoor air must be removed from the house trough these rooms either by mechanical exhaust or by natural ventilation. When applying mechanical exhaust the requirements to the volume flow rate are 20 l/s from kitchen, 15 l/s from bathroom and 10 l/s from toilet. Applying natural ventilation requires a ventilation duct with a cross sectional area of at least 200 cm2 in each of the above mentioned rooms. Usually, 200 cm2 corresponds to the net cross sectional area of a 15 x 15 cm duct. Extractor fans intended for periodic use are not considered as real exhaust systems. Normal procedure when applying mechanical ventilation is to install adjustable valves in the air vents. The setting of the valves must correspond to the air flow required by the system. Normally, these settings are not to be changed at a later stage. Irrespective of the ventilation in the kitchen being natural or mechanical the kitchen shall be supplied with a hood with extraction to the outside. Natural ventilation requires both a ventilation duct and a duct for the hood. The hood must not be connected to the ventilation duct. A hood duct is usually automatically blocked during the periods when the hood is not in use. If a hood is considered an integral part of a mechanical exhaust system the volume flow rate through the hood must be continuous and at least 20 l/s. In this case the noise level of the hood must not exceed 30 dB in kitchen and habitable rooms. Where the kitchen is a part of a living room the requirements, stated in figure 101 concerning the supply of fresh air and the removal of indoor air, are applicable. In kitchens, bathrooms and toilets an opening of 100 cm2 from access rooms is required. The demand can be fulfilled by establishing a crack beneath the door or by installing an air vent in

the door or in the wall. The purpose of establishing this opening is to secure that the removal of air from the rooms functions according to the intention, and to secure that the extraction of air from the rooms contributes to the supply of fresh air to the habitable rooms. The requirement concerning a ventilation opening from access rooms only applies to the above mentioned rooms as it is mainly the doors to these rooms which are kept closed, but in general it is considered a good idea also to install air vents in the doors or in the walls between other rooms. This is because closed doors in some parts of the house may have an adverse effect on the functionality of the ventilation system. Air vents between habitable rooms should be sound proofed. In cases where one of the walls surrounding a room is an external wall it is a must to supply outdoor air to that room For this particular reason at least one of the walls in a bathroom should be an exterior wall. The fresh air vent in these rooms should only be opened when there is a need for extra ventilation as an open air vent reduces the airflow in the habitable rooms. Other rooms, crawl spaces and basements The rules applying to a toilet concerning the supply of removal of air also applies to a scullery. Basements shall be ventilated to the outside through air vents with the same cross sectional areas as those in a habitable room. As basements are not habitable rooms the requirement for draught-free air supply is not applicable. Ventilation (mechanical or natural) must be established in at least one basement room. Fresh air vents and ventilation ducts Fresh air vents The primary function of the fresh air vents is to secure a controlled supply of outdoor air to the dwelling. Also, the fresh air valves give the occupants a possibility of regulating the distribution of the supplied outdoor air. Fresh

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air vents must not be confused with the adjustable valves which are used in connection with injection of air. A fresh air vent deflecting the supplied outdoor air towards the ceiling or parallel to the exterior wall is normally considered the best solution, see SBI Report 196, “Udeluftventiler, 1989” When the air is deflected it will be mixed with the air in the room and also the airspeed outside the living zone is being reduced. This reduces the risk of draught inside the living zone. It may also be an advantage to install the fresh air vent above a radiator, which will often be above a window (since radiators are normally placed below windows and there is too little space between the window and the radiator). From a constructional point of view it is, however, often impossible to install the vent above the window, see page 45 and 50. Before installing an air vent above a window the construction must always be closely examined. A fresh air vent should always be supplied with an insect screen and also with filters securing the filtration of possible particles in the supplied air. A fresh air vent should always be insulated against condensation. Condensation may cause the fouling up of paint and wall cladding and may cause movable parts inside the vent to freeze and block. Also, frequent condensation may damage the valve as well
External grate with insect screen Sound proofing

as the surrounding building construction due to possible ingress of water. In the case of requirements on soundproofing against noise from the outside, see page 46, it may be necessary to use sound proofed air vents. Figure 104 shows an example of a condensation insulated air vent which is also sound proofed. A fresh air vent should be adjustable and it should be easy to operate from floor level. Fresh air vents should be simple and easy to maintain and clean. If so, the occupants will be encouraged to use the vents as intended and at the same time get full value of the advantages of being able to regulate both the volume flow rate as well as the distribution of the supplied outdoor air.

Filter Insulation against condensation

Figure 104. Example of a fresh air vent with insect screen, filter, insulation against condensation and sound proofing

Ventilation ducts Ventilation ducts used for natural ventilation shall be placed and designed in such a way that the two forces from wind and from thermal buoyancy are fully utilized. The ducts should be so placed that the heat from surrounding rooms can contribute to the thermal buoyancy in the ducts. Also the ducts should be taken to the ridge without or with very few bends – this will often be near the centerline of the house. Bends in the ventilation ducts will result in pressure loss and a reduced volume flow rate. When, for practical reasons, it is not considered possible to lead the duct vertically without any bends, a soft curve shall be applied and a total of two bends is accepted. The angle between the vertical plane and the duct should not exceed 45o, see figure 105. Preferably, ventilation ducts should be constructed as rigid ducts but flexible ducts may be used. Special care should be taken when mounting flexible ducts. The length of the duct must be carefully calculated and care must be taken that the ducts are generally supported and fixed. Ventilation ducts shall be insulated against condensation where they pass unheated rooms

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Figure 105. Examples of running the ventilation duct. Unavoidable bends shall be soft curves and the angle between the vertical plane and the duct must not exceed 45o. A maximum of two bends is accepted. such as an attic. The part of the duct which protrudes through the roof must also be insulated against condensation. The insulation of this part will at the same time contribute to maintaining the thermal buoyancy forces. Ventilation ducts should terminate as close to the roof ridge as possible and the level of the mouth should at least correspond to that of the ridge. In general, ventilation ducts, including ducts for natural ventilation, shall be so designed that they do not cause inconvenience to the surroundings. Pollution from building materials A lot of the materials used in the construction of a building emit contaminants. Building materials must not emit gasses, vapors particles or ionized radiation which can lead to an unsatisfactory and unhealthy indoor climate. That is one of the reasons why it is recommended only to use materials where normal ventilation is adequate to remove released contaminants to a level whereby they no longer pose a threat to health or comfort. The emission from a material is characterized by the amount of substance emitted per time unit. The emission normally decreases

proportionally to the elapsed time and at the beginning it is the volatile components which are predominant. The fact that emission decreases proportionally to elapsed time is the basic principle used by “Dansk Indeklima Mærkning” (Danish Indoor Climate Classification) which is described in the subsequent paragraph. Danish Indoor Climate Labelling The labelling indicates a time value relevant to the indoor climate when using a specific building material. This means the time it takes for the emission of contaminants to the air from a material in a standard room to reach below defined levels for smell, irritation and other health hazardous effects. In this way the designers of buildings as well as the potential users are informed about the expected duration of indoor climate problems caused by the use of a certain building material. Based on this information they will be able to decide which precautions should be taken for instance in terms of increased ventilation during a set period of time. Requiring a complete product description including information about the applicability of a certain building material is being used as a mean to avoid the emission of gasses as a consequence of the wrong application of the said building material. The product description must also contain such aspects as guidance concerning storing, transport and mounting. Additionally, information is required concerning the cleaning and maintenance of the building material. Figure 106 shows an example of a certificate. A complete list of materials which have been branded can be obtained from “Dansk Indeklima Mærkning” DTI, Byggeri. The labelling procedure is explained in more detail in the leaflet “Dansk Indekilma Mærkning” – en introduktion til brugere, Tåstrup, 1995 (Danish Indoor Climate Labelling – an introduction to users, Tåstrup, 1995)

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Figure 106. Example of a certificate issued by Dansk Indeklima Mærkning (the Danish Indoor Climate Labeling).

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Heat producing appliances and chimneys
Heat producing appliances include all types of stoves, fireplaces, boilers for central heating and the like. According to the Building Regulations for Small dwellings, heat producing appliances and chimneys shall be so constructed that they cause no danger of fire, explosion, poisoning or other health hazards. Materials used must be resistant to flue gases, fire, heat and corrosion. This chapter deals with the installation of heat producing appliances and chimneys used for oil and solid fuel heating. Regarding the installation of gas heat producing appliances and flue ventilation reference is made to regulations in “Gasreglementet”, section A, 1991, 1st amendment, March 1991 and 2nd amendment, May 1995, “Danmarks Gasmateriel Prøvning” (Danish institute for the testing of materials used in gas installations). This SBI-direction does not cover special rules applying to the installation of oil tanks and pipes for oil supply. Heat producing appliances When heating with solid or liquid fuel a clear distinction is made between closed and open heat producing appliances. In an open heat producing appliance it is not possible to close the hearth with doors or similar from the room, which is to be heated. Closed heat producing appliances are central heating boilers as well as stoves equipped with doors. The size of a closed heating appliance is characterised by the stoking effect, that is, the heating effect released at combustion. The stoking effect is proportional to the consumption of fuel. When stoking with oil the stoking effect is approximately 10 kW at a consumption of 1 litre of oil per hour, and when stoking with solid fuel the equivalent value is 4 kW at a consumption of 1 kg wood per hour. When pressure atomising burners are used for oil heating the effect is determined by the

ejector nozzle size. It is difficult to determine the exact stoking effect of manually fed stoves and boilers (solid fuel) given the fact that feeding tends to be uneven and uncontrolled. A small stove can have a maximum wood consumption of 3 kg per hour and thus have a stoking effect of 12 kW. Any stove produced and tested according to DS 887, “Solid fuel stove for room heating - Part 1: Requirements” will have a stove label containing information about the nominal effect in kW. Setting up Heat producing appliances can be set up in living rooms, kitchens, sculleries and basement rooms provided the ventilation is sufficient to give adequate air for combustion. This can for example be achieved by supplying the room with an adequately dimensioned adjustable fresh air vent or by supplying combustion air through a ventilation duct from the outside. Installation of heat producing appliances on, or close to combustible material, is allowed provided the heat emission does not cause temperatures in excess of 80oC on any combustible material. In the case of fireplaces and stoves this requirement is considered to be fulfilled when the distance from any exterior part of the fireplace or stove to combustible material is at least 500 mm. In the case of masonry fireplaces this distance is measured from the internal surface of the fireplace. Stoves constructed in accordance with DS 887 can be installed according to the distances specified on the stove label. Safety distances are always calculated to combustible material whether visible or concealed behind a non-combustible covering. The distance requirements do not apply to skirtings. The floor below stoves and fireplaces must be non-combustible or firmly covered by a noncombustible material such as stone or stone aggregate or a steel or copper plate to protect against falling embers. The covering shall extend at least 300 mm in front of closed hearts

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and at least 500 mm in front of open hearts. Furthermore, the covering shall extend at least 150 mm to either side of the hearth opening. Connection to chimney Heat producing appliances for solid and liquid fuel shall always be connected to a chimney extending above the roof. The connecting pipe between the heat producing appliance and the chimney is called a flue pipe. Flue pipes must be installed in such a way as to facilitate easy maintenance and cleaning. Flue pipes should be short and with as few elbows or curves as possible. When cleaning cannot be done via the heat producing appliance, the flue pipe shall be equipped with sufficient cleanout doors. Inside the room where the heating appliance is installed, flue pipes less than 1.0 m long can be made from minimum 1.0 mm steel plate or similar. When pipes are longer than 1.0 m, a thicker plate should be used, for example 2.0 mm. The clearance between non-insulated flue pipes and combustible material shall be at least 300 mm. When two or more heating appliances are connected to opposite sides of the chimney the connection shall be continuous in such a way that the vertical distance between connections shall be at least 250 mm. An open fireplace shall be connected to a separate chimney with no other connections from heating appliances. Gas heating appliances shall be connected to a flue according to the regulations stated in “Gasreglementet” (the Gas Regulations). Chimneys Chimneys shall be sufficiently high to ensure adequate flue. Also, chimneys shall be sufficiently high (in relation to roofs and surroundings) to ensure that the smoke is quickly dispersed and diluted into the atmosphere. Cross-sectional area The cross-sectional area of the chimney must be adjusted to the amount of smoke. The cross sectional area must be sufficiently large to

accommodate for maximum smoke flow. Also space must be reserved for soot deposit. On the other hand the cross sectional area must not be excessively big as this may result in condensation and tarry soot. Stoking with solid fuel requires a larger cross sectional area than oil combustion. The cross sectional area should be kept within the limits stated in figure 107 for oil stoking and solid fuel stoking. In case of circular cross sections the limits equal the limits of the diameter stated in figure 108. The dimensioning is based on the stoking effect of the connected heating appliance or on the total effect of all connected heating appliances. When both oil and solid fuel stoked heating appliances are connected to the same chimney the cross sectional area can be determined as a compromise between the stated values for oil stoking and solid fuel stoking. However, it will usually be a better solution to connect the appliances to separate chimneys.

Chimney cross sectional area cm2

Solid fuel

Oil

Stoking effect, kw

Figure 107: Cross sectional area limits for small chimneys used for oil and solid fuel stoking. Sizes are determined as a result of the total stoked effect at maximum load. The bold horizontal lines represent minimum requirements in Building regulations for Small Dwellings. The values apply to closed heating appliances

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Solid fuel

Chimney cross sectional area cm2

Oil

Stoking effect, kw

Figure 108: Limits for the internal diameter of small chimneys with a circular cross section oil and solid fuel stoking. The bold horizontal lines represent minimum requirements in Building regulations for Small Dwellings. The values apply to closed heating appliances. Example: An oil stoked central heating boiler consuming 2 litres of oil per hour (with oil burner active) has a stoking effect of 20 kW. As stated in the figure the diameter should not be chosen below 100 mm and not above 140mm. If a stove is also connected with a maximum consumption of 4 kg wood per hour the total effect is 36 kW and a diameter of 175 mm can for example be chosen. The cross sectional area of the chimney and the flue pipe to which an open fireplace is connected shall be at least 300 cm2. If the free opening of the fireplace is not larger than 2500 cm2, the cross sectional area can be reduced to 175 cm2. The free opening refers to the opening through which the combustion air is flowing into the heating appliance. When the heating appliance is equipped with openings on several sides the area is measured as the sum of all openings. Cross sectional areas of 300 cm2 and 175 cm2 correspond to diameters of 195 mm and 150 mm respectively.

Height A slight negative pressure should be established in the combustion chamber of a heating appliance and in the entire flue system - not only for the sake of smoke transportation but also for safety precautions by preventing smoke drifting from the heat appliance, the flue pipe or the chimney into the surrounding rooms. The low pressure is established by the thermal buoyancy created by the hot smoke in the chimney. The buoyancy increases with higher smoke temperature and by increasing the chimney height. The chimney of an oil furnace/boiler must suck out the smoke from the boiler while the oil burner fan supplies the combustion air. When stoking with solid fuel the chimney must not only suck out the smoke from the heating appliance - it must also suck the combustion air into the heating appliance through the air intake. Stoves and especially central heating boilers for solid fuel therefore often require higher chimneys than oil furnaces. The chimney height is calculated from the floor on which the heating appliance is placed. Whenever possible, the height should not be less than 5 m. In the case of solid fuel boilers and other heating appliances requiring higher chimneys in order to function safely the manufacturer’s instructions should always be followed. When a house is exposed to wind an overpressure occurs on the windward facade and – at roof pitches above 30o also along the lower part of the roof. The chimney should be sufficiently high to secure that the outlet is placed outside the over-pressure zone. Smoke eddies tend to arise above flat roofs and in the lee side of pitched roofs. Consequently, smoke may be lead down to a level where humans breathe and thus cause inconveniencies. Therefore, the chimney should be taken up above the eddy zone. As a rule-of-thumb the chimney is usually taken up 1 m above the roof ridge or the highest part of the roof. The chimney outlet should under no circumstances be placed lower than the highest point of the roof. If the chimney is placed on a low extension, the height of the chimney shall be determined according to the highest roof ridge of the house.

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Construction Brick chimneys are traditionally constructed with a 252 x 252 mm cross sectional opening and a 108 mm chimney wall inside the house and a 228 mm wall in the chimney pot. This construction is rarely used in new buildings partly because the cross sectional area is too large and partly because the insulation is too poor but also because the wall construction method may cause leakages. Instead bricked chimneys are made either of pre-cast liner elements which can be brick clad or as a traditional brick chimney but with an insulating lining which reduces the cross sectional area, see figure 109. The figure also shows an example of a steel chimney. Chimney elements and chimney linings as well as steel chimneys shall be MK approved and construction/installation shall be carried out in accordance with manufacturer’s instructions.

Figure 109 Examples of chimney cross sections. The figure shows examples of chimney elements and chimney linings. Other types of elements and linings do exist. However, all elements and linings must be MK-approved. a) Thin-walled lining: to be lowered into existing brick chimney. b) Thick-walled lining: built-in during the construction of a traditional brick chimney. c) Pumice concrete element where the cavity is filled with a lean clinker concrete. d) Ceramic tile/ concrete element with air filled cavities. e) Ceramic tile/ concrete element with mineral wool in cavity. f) Steel chimney. g) Pumice concrete element with air filled cavities.

Chimneys are usually cleaned from the top. In houses with non-habitable attics above the collar beams it is, however, practical to construct the chimney in such a way that it can be cleaned from a cleanout door in the attic. Care must be taken to secure safe access for the chimneysweeper to the chimney. It may be necessary to mount steps on the roof and to equip tall chimney pots with corrosion protected rungs. The mounting of rungs is only possible on solidly build chimney pots. Rungs cannot be mounted on prefabricated chimney elements and safe fixing in masonry is only possible provided the brickwork has a minimum thickness of 228 mm. During cleaning the soot is swept down inside the chimney. This soot must be removed through a cleanout door at the bottom of the chimney. When a steel chimney is mounted directly on top of a furnace the soot is swept down into the furnace which will then be cleaned together with the chimney. When a chimney is not constructed vertically it may be necessary to install extra cleanout doors. Cast iron double cleanout doors are used for brick chimneys. The clearance between combustible material and steel or brick chimneys shall be at least 100 mm. Clearance between cleanout doors and combustible material shall be at least 200 mm. Distances are measured from the external side. Beams, rafters and stair stringers may however be placed directly against brick chimney walls provided the wall is at least 228 mm thick or provided the chimney is constructed similarly, for example a chimney element with at least 108 mm brick cladding or as a brick chimney with a 108 mm wall supplied with a lining. In the latter case the chimney must be insulated from any combustible material using at least 20 mm mineral wool. The edge of combustible claddings with a maximum thickness of 30mm can be placed directly against brick chimneys. The distance to steel chimneys shall be at least 50 mm. Thatched roofs In roof coverings which cannot be classified as a class T roof covering like for example thatched

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roofs, chimneys shall be so constructed and installed that adequately fire safety is achieved. Brick chimneys: From minimum 300 mm below the roof cover and upwards the walls shall be constructed of at least 228mm masonry or of approved chimney elements clad with at minimum 108 mm brickwork. Under the roof the masonry shall be protected against cracks by application of at least 30 mm reinforced plastering. Steel chimneys: From minimum 300 mm below the roof cover and upwards the chimney shall run through a duct, which has a diameter of at least 200 mm more than the diameter of the chimney. Chimneys erected within a distance of 6m from a thatched roof or other easily combustible roof material shall be extended at least 0.8 m above the roof ridge and should not be equipped with chimney covers, chimney caps, chimney spark arresters or the like as such devices may result in increased risk of fire spread if a chimney fire occurs. For more details on the fireproofing of thatched roofs reference is made to “Brandteknisk Information nr. 29, Brandsikring af stråtage” (Fire technical information no 29, Fireproofing of thatched roofs, The Danish Institute for fire testing)

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Enclosure A. Loads Sorry - this chapter is not yet available in the English version.

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Enclosure B. Fire

In terms of fire building components are classified according to their fire resistance and according to the way a given surface (cladding) reacts to fire as these two characteristics significantly influence how fast a fire develops – especially during the initial phases. The construction examples in this SBI direction comply with current demands concerning fire resistance and fire-technical qualities of the claddings. The fire resistance of building components The ability of a building component to resist fire penetration and to maintain bearing capacity during a fire determines how much time will be available to rescue persons from the building and how much time the fire brigade will have in order to control the fire. This characteristic is termed “fire resistance” and is stated by the number of minutes during which the building component prevents penetration of the fire and – for load bearing structures – maintains sufficient load bearing capacity. The terms BS (fire safe) or BD (fire retarding) state that a building component contain nonflammable materials only (BS) or part of the building component may contain flammable materials (BD). Fastening of mineral wool In BD constructions the insulation shall be mineral wool in batts and it shall be fastened with steel wire or furring as shown in figures 112 and 113. In walls the insulation may be fastened by means of slanted nailing as shown in figure 114. Where rockwool is required the density shall be at least 30 kg/m3.

Ø 2 mm steel wire

Figure 112. Mineral wool in BD constructions can be fastened by means of 2 mm steel wire per 300 mm. Cramp dimensions are stated in table 19.

Furring strips

Figure 113. Mineral wool in BD construction 30 can be fastened by means of 19 mm furring strips per 300 mm. Nail dimensions are stated in table 19.

Nails, min. 30 mm into wood min. 35 mm into mineral wool

Figure 114. Mineral wool in walls can be fastened by means of slanted nailing per 300 mm. The nails must penetrate the mineral wool by minimum 35 mm and the wood by minimum 30 mm. Slanted nailing from one side of the wall is sufficient
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Table 19. Dimensions of nails and cramps (in mm) for the fastening of furring and wire. According to Wood and Fire Walls BD 30 2,8 x 50 2,0 x 25 BD 60 4,2 x 50 Floor partitions BD 30 2,8 x 65 3,4 x 35 BD 60 4,8 x 65

Nails Cramps

The fire-technical qualities of claddings (coverings) Claddings are divided into class 1 covering and class 2 covering where class 1 covering is the best. In the following a number of examples representing the two types of claddings are presented. It must be stressed that stated thicknesses are minimum requirements. Class 1 covering A class 1 covering is defined as a covering made from hardly combustible, moderately heat developing and moderately smoke developing material, which, during a standardized fire test for 10 minutes, will protect any material behind the covering from being ignited. Examples: − Reeds and 12 mm plaster − 9 mm plaster boards (gypsum board) − Surfaces of masonry, light weight concrete and concrete with or without plaster. Class 2 covering A class 2 covering is defined as a covering made from a normally flammable, normally heat developing and normally smoke developing material which, during a standardized fire test for 10 minutes, will protect any material behind the covering from being ignited. Examples: − 21 mm tongued and grooved boards − 15 mm tongued and grooved boards with not more than 25 mm underlying cavity. − 9 mm chipboards with a density of minimum 600 kg/m3. − 9 mm fibreboards with a density of minimum 600 kg/m3 − 9 mm plywood with a density of minimum 500 kg/m3

Wooden coverings shall be so fixed that they do not loosen due to the deformations caused by a fire. Fixing may be done by the use of nails, screws or clamps in rows as shown in figures 115 and 116. When using profiled class 2 coverings the surface of the inflammable material is increased. Consequently, a fire will be able to develop faster. Hence, profiling is only allowed within certain limits, see figure 117. On top of class 2 coverings it is accepted to mount wallpaper, burlap or a similar thin coatings without consequence for the firetechnical qualities.

Figure 115. Fastening a wooden (board) lagging by the use of nails, screws or staples, marked with black dots. Each board is fastened at the ends and at every 1000mm.

SBI Direction 189 KLJ

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Max. 200 mm

Max 150 mm

Apart from the here mentioned examples a number of similar covering systems do exist – all approved by the Ministry of Housing. All coverings or the packing material of the same shall carry an indication of approval according to issued certificate.

Max 600mm

Max 150 mm

Figure 116. Fastening a board covering by the use of nails, screws or staples, marked with black dots. Distances according to supplier s instructions or at maximum 150 mm along edges and not more than 200 mm along intermediate supports. The distance between the rows must not be more than 600 mm.

Max. 200 mm Max. 600 mm

Max 200mm Max. 1

a.

Profiled boards with underlying cavity. a1 + a2, i.e. the parts of the board where the thickness is less than 21 mm must not represent more than 20 % of the board width a. b. Profiled boards with no more than 25 mm underlying cavity. a1 + a2, i.e. the parts of the board where the thickness is less than 15 mm must not represent more than 20 % of the board width a. c. Profiled board covering with underlying cavity. a1 + a2, i.e. the part of the board where the thickness is less than 9 mm must not represent more than 20 % of the distance a.

Figure 117. Profiling of class 2 coverings. The profiles must under no circumstances increase the surface area by more than 25 percent.

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Enclosure C. Acoustics Sorry - this chapter is not yet available in the English version.

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Enclosure D. The stabilising system Sorry - this chapter is not yet available in the English version.

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Enclosure E. Heat requirements Sorry - this chapter is not yet available in the English version.

SBI Direction 189 KLJ Translation KLJ
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Summary
SBI Direction 189: Single family houses. Insulation, moisture protection, acoustics, fire resistance, ventilation and strength. This SBI Direction provides guidance, with examples, on designing single family houses to conform with the Building Regulations for Single Family Houses, 1998 (Building Regulations for Small Dwellings – BRS-98) The direction deals with detached, semi-detached and terraced houses with one or two storeys and a basement. The ridge height is limited to 8,5 m. The details shown in the direction are only examples of how to fulfill the requirements of the Building Regulations. There are many other solutions as well. The direction deals first with the structural system, paying special attention to design for wind loads. The basic parts of the house are then discussed, i.e. foundations and drainage, ground floor slab, external and internal walls, parly walls and roof structure, including attic living space. It is shown how the ground floor can be constructed as a slab directly on the ground or over a crawl space or a heated basement. In these sections, specifications are given for the different parts and examples arc provided of how the parts can be joined together to meet the requirements concerning insulation, moisture protection, tire resistance, etc. Documentation of compliance with the requirements concerning heal insulation can be worked out in three different ways. These are described and examples are given of their consequences. The direction also deals with bathroom construction and provides information on choosing glass with sufficient safely against failure. Lastly, methods for establishing natural ventilation in houses are described and some requirements are given concerning chimneys.

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