Wood Sheets
Content
Wood-based sheet
materials
CHOOSE
AND USE
UP-TO-DATE
INFORMATION
FOR BUILDERS
Sheet materials are
manufactured from solid
timber and/or from recycled
timber with the addition of
an adhesive.
Making the right choice
The most commonly used
sheet materials are plywood,
Oriented Strand Board (OSB)
particleboard (chipboard) and
fibreboard (MDF – medium
density fibreboard).
For structural applications you must use structural grades of sheet
These materials are widely
used in construction,
with different grades for
different uses.
you need to ensure the product is
Using the right product for
the job is essential. This
information sheet describes
the most commonly used
sheet materials and some of
their applications.
resistance.
To comply with Building Regulations it is essential you choose the
right type of timber or timber product. Look also for certification
markings (i.e. FSC or PEFC) to show timber is from legal and
sustainable sources.
materials, appropriate for their end use. In domestic situations the
critical areas are usually in roofs, walls and floors, but structural
sheet materials may also be required in the construction of other
structures too.
When selecting sheet materials,
suitable for the job. You also need
to take into account non-structural
characteristics, like appearance,
moisture resistance, and fire
Building Regulations require all timber sheet materials specified for
use in construction to be fit for their intended use and for the
conditions they will be used in. They must comply with the
Construction Products Regulations and the most common way to
achieve this is through compliance with BS EN 13986. The CE marks
on sheet materials are linked to this standard.
Sustainable timber
Timber is the most sustainable building product available. It is
naturally renewable – over 97% of softwood timber used in the
UK comes from Europe, where the forest area is increasing by the
equivalent of 100 football pitches an hour.* For reassurance for
softwoods and hardwoods look for certification labels like FSC
(Forest Stewardship Council) or PEFC (Programme for the
Endorsement of Forest Certification).
*IIED & ECCM, Using Wood to Mitigate Climate Change, 2004 and MCPFE/UNECE-FAO State of Europe’s Forests, 2003.
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
Produced by TRADA, the Timber Research and Development Association (www.trada.co.uk)
in conjunction with wood for good (www.woodforgood.com)
Types of wood-based sheet materials
The following descriptions are accompanied by
Plywood
a more comprehensive table of applications and
Plywood is a versatile sheet material. Softwood
conditions of use, as well as appropriate standards.
plywood is usually made from European grown
Spruce, whilst Birch is a common hardwood plywood.
OSB (Oriented Strand Board)
Spruce is less decorative than Birch and is used in
Consists of resin-bonded sheets made up of small,
construction where a visual appearance is not so
thin strands of wood, compressed into layers to form
important. Birch plywood can have a clearer, knot
a mat. It has good dimensional stability and no knots
free appearance, depending on the grade selected.
or voids in the structure. Different grades and
Both plywoods have grades to suit decorative needs.
thicknesses suit each use depending on the strength
required for the particular structural application.
Hardwood or hardwood faced plywood is usually
OSB has good strength properties and is low cost.
produced in the Far East, South America and China*
and is generally darker in colour than softwood
plywood. (* China now produces plywoods made
from Russian Spruce and Birch, as well as Radiata pine
from New Zealand and veneers from South America).
Plywood used in formwork
Appearance and strength are less of an issue here
although durability, glue bond performance and
resistance to decay may have to be considered.
Suitable sheets are available from Scandinavia,
North America and the Far East.
Structural plywood
Particleboard (chipboard)
Consists of chips compressed together with resin.
Has smooth surfaces without knots or voids.
Usually available for structural and non-structural
applications. Most chipboards incorporate some
recycled chipped timber.
All plywood for structural load bearing applications
(i.e. walls, floors and roofs) must be strong enough
for the loading. Always use plywoods that are listed
in BS 5268-2:2002 – typically those from Canada,
Finland, Sweden and the USA. They need to also
2
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
Types of wood-based sheet materials
comply with the Construction Products Regulations
machined, drilled, cut and filled easily without
(CPR) by meeting the requirements of BS EN 13986,
damaging the surface. Also available in finished
or by other means. The CE mark demonstrates CPR
product e.g. skirtings, architraves and other mouldings.
compliance and that those structural plywoods are fit
Fire rated and external grades are available. MDF is
for a particular purpose.
sometimes colour coded by dyes in the board layers
to indicate its use:
Green – for moisture resistant
1234 - CPD - 5678
Any company
PO Box ??
Any Town
Country
CE logo
Grey – for exterior use
No of Notified Body Directive - Product/Certificate
of Conformity No
Red – sheets with flame retardant chemicals
Manufacturer’s name
and address
Construction Products Regulations (see table
on page 4).
02
EN 13986
Year CE mark affixed
EN 636-2
Plywood standard
for humid conditions
E1
Plywood for use as
structural flooring
If used in construction MDF must comply with
Harmonised European Standard
Formaldehyde class
Intended end use application
Hardboard
Made from wood fibre extracted from chips or
pulped wood waste. Non-structural for internal use
such as flooring, underlay and shopfitting, although
enhanced performance hardboards can be used
where higher strength is needed. Enhanced boards
find applications as components within structural
Marine plywood (certified to BS 1088)
Although clearly intended for wet applications,
marine plywood is not suitable for general structural
applications unless it has been tested and shown to
meet the requirements of BS EN 13986.
members e.g. I beams, exterior soffits and signage.
Blockboard and laminboard
Made up of a core of softwood strips up to 25mm
wide, placed edge to edge, sometimes sandwiched
between softwood or hardwood veneers and glued
MDF (Medium Density Fibreboard)
together under high pressure. Mainly used for
An engineered, stiff, flat sheet. Knot free, made from
non-structural internal applications.
wood fibres. It has no surface grain and can be
Storing
Store sheet materials flat, on bearers or in ‘A’ frames.
As wood is sensitive to changes in moisture, try to
acclimatise any wood product to the temperature
and humidity in the room where it will be installed,
for a few days only.
Fixings
Secure by screws, nails and glues, using the many
different specialist products developed for these
products. Metal fixings such as screws and nails
should be long enough to allow about 20mm
penetration into the substrate, or to have an overall
length of about 2.5 times the sheet thickness. Where
engineering design requires a certain fastener type
and spacing, this must be adhered to.
3
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
Types of wood-based sheet materials
PRODUCT
USES
CONDITIONS
USE CLASSES (where applicable)
STANDARDS
OSB (Oriented Strand Board)
OSB/2
Exhibition panels, internal walls, shelving, site
hoardings, packing, cases, garden sheds
Dry situation, structural
applications
Class 1
BS EN 300:1997
OSB/3
Timber frame structural sheathing, flat and
pitched roofs, wall sheathing, flooring, caravans
Load bearing use in humid
conditions
Class 1 & 2
BS EN 300:1997
Type P1
Standard grade, general purpose joinery &
furniture
Dry interior use, not structural Class 1
BS EN 312:2003
Type P2
Furniture grade, usually with melamine or
decorative veneers. Kitchen and bedroom
cabinets, shelving
Dry interior use, not structural Class 1
BS EN 312:2003
Type P3
Moisture resistant, uses similar to above
Interior use, not structural
Class 1 & 2
BS EN 312:2003
Type P4
Flooring applications, loft planks, bathrooms
Dry interior use, structural
Class 1
BS EN 312:2003
Type P5
Flooring applications, kitchens, bathrooms
For use in humid conditions,
structural
Class 1 & 2
BS EN 312:2003
Complies with
BS EN 636 1G
General purpose joinery
Interior use, not structural
Class 1 dry conditions
20%-65% relative humidity
BS EN 636:2003, BS EN
5268 part 2, Eurocode 5,
BS EN335 2&3 (Use
classes), BS EN 635
(surface appearance)
Complies with
BS EN 636 3G
Fascias, site hoardings
Exterior use in humid
conditions, not structural.
Take into account durability
of surface species BS EN 635
Class 3 moisture level 20%+,
above ground, uncovered
As above, with glue line
to BS EN 314-2 class 3
Complies with
BS EN 636 2G
Soffits
As above
Class 1 & 2
As above, with glue line
to BS EN 314-2 class 2
Complies with
BS EN 636 3S
Cladding, walkways
Fully exposed, exterior
conditions above ground, not
covered, structural
Class 3 exterior conditions
above 20% moisture level.
Class 1 & 2
As, above with glue line
to BS EN 314-2, class 3
BS EN 1099 Durability
Complies with
BS EN 636 3S
Flooring, wall sheathing, roof sarking
Covered, above ground,
structural, semi exposed
Class 1 & 2 risk of wetting,
humid conditions, 20-90%
relative humidity
As above, with glue line
to BS EN 314-2 class 3
Chipboard
Plywood
MDF (Medium Density Fibreboard)
Type MDF
General purpose, joinery, shop fronts, signage,
door parts, fascias
Dry conditions, interior use
not structural
Class 1
BS EN 622-5:1997
Type MDF H
General purpose, joinery, kitchens, bathrooms
Humid conditions,
not structural
Class 1 & 2
BS EN 622-5:1997
Exterior MDF
General purpose, joinery, shopfitting, signage,
door parts, fascias
Exterior conditions, for more
information see
manufacturer’s details
Class 1, 2 & 3
See manufacturer’s
literature or
www.wpif.org.uk
General purpose, panelling, boxing in pipework
Interior use, not structural
Class 1
BS EN 622-2:1997
Interior use, not structural
Class 1
BS EN 314-2 class 1
Hardboard
Type HB
Blockboard / Laminboard
Complies with
BS EN 636 1G
General joinery, door blanks, shopfitting
For further information on all the sheet materials, specifications, sizes and thicknesses, fixing locations, support details and
spans, especially in structural applications, ALWAYS refer to the manufacturer’s own literature or website or enquire through
your local merchant. Visit www.trada.co.uk, www.woodforgood.com or the Wood Panel Industries Federation
www.wpif.org.uk/panelguide.asp for additional advice.
Choose and Use
is a series of information sheets
for builders produced by TRADA, The Timber Research and
Development Association.
They offer up-to-date advice on how to select the right
timber and timber products for different applications.
You can often save time and money by choosing the
correct timber material or timber products as well as
ensuring you comply with current Building Regulations
and Building Codes. For more information about
specific products visit www.trada.co.uk or contact
your local supplier.
4
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
materials
CHOOSE
AND USE
UP-TO-DATE
INFORMATION
FOR BUILDERS
Sheet materials are
manufactured from solid
timber and/or from recycled
timber with the addition of
an adhesive.
Making the right choice
The most commonly used
sheet materials are plywood,
Oriented Strand Board (OSB)
particleboard (chipboard) and
fibreboard (MDF – medium
density fibreboard).
For structural applications you must use structural grades of sheet
These materials are widely
used in construction,
with different grades for
different uses.
you need to ensure the product is
Using the right product for
the job is essential. This
information sheet describes
the most commonly used
sheet materials and some of
their applications.
resistance.
To comply with Building Regulations it is essential you choose the
right type of timber or timber product. Look also for certification
markings (i.e. FSC or PEFC) to show timber is from legal and
sustainable sources.
materials, appropriate for their end use. In domestic situations the
critical areas are usually in roofs, walls and floors, but structural
sheet materials may also be required in the construction of other
structures too.
When selecting sheet materials,
suitable for the job. You also need
to take into account non-structural
characteristics, like appearance,
moisture resistance, and fire
Building Regulations require all timber sheet materials specified for
use in construction to be fit for their intended use and for the
conditions they will be used in. They must comply with the
Construction Products Regulations and the most common way to
achieve this is through compliance with BS EN 13986. The CE marks
on sheet materials are linked to this standard.
Sustainable timber
Timber is the most sustainable building product available. It is
naturally renewable – over 97% of softwood timber used in the
UK comes from Europe, where the forest area is increasing by the
equivalent of 100 football pitches an hour.* For reassurance for
softwoods and hardwoods look for certification labels like FSC
(Forest Stewardship Council) or PEFC (Programme for the
Endorsement of Forest Certification).
*IIED & ECCM, Using Wood to Mitigate Climate Change, 2004 and MCPFE/UNECE-FAO State of Europe’s Forests, 2003.
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
Produced by TRADA, the Timber Research and Development Association (www.trada.co.uk)
in conjunction with wood for good (www.woodforgood.com)
Types of wood-based sheet materials
The following descriptions are accompanied by
Plywood
a more comprehensive table of applications and
Plywood is a versatile sheet material. Softwood
conditions of use, as well as appropriate standards.
plywood is usually made from European grown
Spruce, whilst Birch is a common hardwood plywood.
OSB (Oriented Strand Board)
Spruce is less decorative than Birch and is used in
Consists of resin-bonded sheets made up of small,
construction where a visual appearance is not so
thin strands of wood, compressed into layers to form
important. Birch plywood can have a clearer, knot
a mat. It has good dimensional stability and no knots
free appearance, depending on the grade selected.
or voids in the structure. Different grades and
Both plywoods have grades to suit decorative needs.
thicknesses suit each use depending on the strength
required for the particular structural application.
Hardwood or hardwood faced plywood is usually
OSB has good strength properties and is low cost.
produced in the Far East, South America and China*
and is generally darker in colour than softwood
plywood. (* China now produces plywoods made
from Russian Spruce and Birch, as well as Radiata pine
from New Zealand and veneers from South America).
Plywood used in formwork
Appearance and strength are less of an issue here
although durability, glue bond performance and
resistance to decay may have to be considered.
Suitable sheets are available from Scandinavia,
North America and the Far East.
Structural plywood
Particleboard (chipboard)
Consists of chips compressed together with resin.
Has smooth surfaces without knots or voids.
Usually available for structural and non-structural
applications. Most chipboards incorporate some
recycled chipped timber.
All plywood for structural load bearing applications
(i.e. walls, floors and roofs) must be strong enough
for the loading. Always use plywoods that are listed
in BS 5268-2:2002 – typically those from Canada,
Finland, Sweden and the USA. They need to also
2
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
Types of wood-based sheet materials
comply with the Construction Products Regulations
machined, drilled, cut and filled easily without
(CPR) by meeting the requirements of BS EN 13986,
damaging the surface. Also available in finished
or by other means. The CE mark demonstrates CPR
product e.g. skirtings, architraves and other mouldings.
compliance and that those structural plywoods are fit
Fire rated and external grades are available. MDF is
for a particular purpose.
sometimes colour coded by dyes in the board layers
to indicate its use:
Green – for moisture resistant
1234 - CPD - 5678
Any company
PO Box ??
Any Town
Country
CE logo
Grey – for exterior use
No of Notified Body Directive - Product/Certificate
of Conformity No
Red – sheets with flame retardant chemicals
Manufacturer’s name
and address
Construction Products Regulations (see table
on page 4).
02
EN 13986
Year CE mark affixed
EN 636-2
Plywood standard
for humid conditions
E1
Plywood for use as
structural flooring
If used in construction MDF must comply with
Harmonised European Standard
Formaldehyde class
Intended end use application
Hardboard
Made from wood fibre extracted from chips or
pulped wood waste. Non-structural for internal use
such as flooring, underlay and shopfitting, although
enhanced performance hardboards can be used
where higher strength is needed. Enhanced boards
find applications as components within structural
Marine plywood (certified to BS 1088)
Although clearly intended for wet applications,
marine plywood is not suitable for general structural
applications unless it has been tested and shown to
meet the requirements of BS EN 13986.
members e.g. I beams, exterior soffits and signage.
Blockboard and laminboard
Made up of a core of softwood strips up to 25mm
wide, placed edge to edge, sometimes sandwiched
between softwood or hardwood veneers and glued
MDF (Medium Density Fibreboard)
together under high pressure. Mainly used for
An engineered, stiff, flat sheet. Knot free, made from
non-structural internal applications.
wood fibres. It has no surface grain and can be
Storing
Store sheet materials flat, on bearers or in ‘A’ frames.
As wood is sensitive to changes in moisture, try to
acclimatise any wood product to the temperature
and humidity in the room where it will be installed,
for a few days only.
Fixings
Secure by screws, nails and glues, using the many
different specialist products developed for these
products. Metal fixings such as screws and nails
should be long enough to allow about 20mm
penetration into the substrate, or to have an overall
length of about 2.5 times the sheet thickness. Where
engineering design requires a certain fastener type
and spacing, this must be adhered to.
3
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
Types of wood-based sheet materials
PRODUCT
USES
CONDITIONS
USE CLASSES (where applicable)
STANDARDS
OSB (Oriented Strand Board)
OSB/2
Exhibition panels, internal walls, shelving, site
hoardings, packing, cases, garden sheds
Dry situation, structural
applications
Class 1
BS EN 300:1997
OSB/3
Timber frame structural sheathing, flat and
pitched roofs, wall sheathing, flooring, caravans
Load bearing use in humid
conditions
Class 1 & 2
BS EN 300:1997
Type P1
Standard grade, general purpose joinery &
furniture
Dry interior use, not structural Class 1
BS EN 312:2003
Type P2
Furniture grade, usually with melamine or
decorative veneers. Kitchen and bedroom
cabinets, shelving
Dry interior use, not structural Class 1
BS EN 312:2003
Type P3
Moisture resistant, uses similar to above
Interior use, not structural
Class 1 & 2
BS EN 312:2003
Type P4
Flooring applications, loft planks, bathrooms
Dry interior use, structural
Class 1
BS EN 312:2003
Type P5
Flooring applications, kitchens, bathrooms
For use in humid conditions,
structural
Class 1 & 2
BS EN 312:2003
Complies with
BS EN 636 1G
General purpose joinery
Interior use, not structural
Class 1 dry conditions
20%-65% relative humidity
BS EN 636:2003, BS EN
5268 part 2, Eurocode 5,
BS EN335 2&3 (Use
classes), BS EN 635
(surface appearance)
Complies with
BS EN 636 3G
Fascias, site hoardings
Exterior use in humid
conditions, not structural.
Take into account durability
of surface species BS EN 635
Class 3 moisture level 20%+,
above ground, uncovered
As above, with glue line
to BS EN 314-2 class 3
Complies with
BS EN 636 2G
Soffits
As above
Class 1 & 2
As above, with glue line
to BS EN 314-2 class 2
Complies with
BS EN 636 3S
Cladding, walkways
Fully exposed, exterior
conditions above ground, not
covered, structural
Class 3 exterior conditions
above 20% moisture level.
Class 1 & 2
As, above with glue line
to BS EN 314-2, class 3
BS EN 1099 Durability
Complies with
BS EN 636 3S
Flooring, wall sheathing, roof sarking
Covered, above ground,
structural, semi exposed
Class 1 & 2 risk of wetting,
humid conditions, 20-90%
relative humidity
As above, with glue line
to BS EN 314-2 class 3
Chipboard
Plywood
MDF (Medium Density Fibreboard)
Type MDF
General purpose, joinery, shop fronts, signage,
door parts, fascias
Dry conditions, interior use
not structural
Class 1
BS EN 622-5:1997
Type MDF H
General purpose, joinery, kitchens, bathrooms
Humid conditions,
not structural
Class 1 & 2
BS EN 622-5:1997
Exterior MDF
General purpose, joinery, shopfitting, signage,
door parts, fascias
Exterior conditions, for more
information see
manufacturer’s details
Class 1, 2 & 3
See manufacturer’s
literature or
www.wpif.org.uk
General purpose, panelling, boxing in pipework
Interior use, not structural
Class 1
BS EN 622-2:1997
Interior use, not structural
Class 1
BS EN 314-2 class 1
Hardboard
Type HB
Blockboard / Laminboard
Complies with
BS EN 636 1G
General joinery, door blanks, shopfitting
For further information on all the sheet materials, specifications, sizes and thicknesses, fixing locations, support details and
spans, especially in structural applications, ALWAYS refer to the manufacturer’s own literature or website or enquire through
your local merchant. Visit www.trada.co.uk, www.woodforgood.com or the Wood Panel Industries Federation
www.wpif.org.uk/panelguide.asp for additional advice.
Choose and Use
is a series of information sheets
for builders produced by TRADA, The Timber Research and
Development Association.
They offer up-to-date advice on how to select the right
timber and timber products for different applications.
You can often save time and money by choosing the
correct timber material or timber products as well as
ensuring you comply with current Building Regulations
and Building Codes. For more information about
specific products visit www.trada.co.uk or contact
your local supplier.
4
This information sheet provides general advice only and is not specific to the requirements of a particular building project. It is the builder’s responsibility to check compliance with
building regulations and standards. © TRADA Technology and wood for good.
