Section Contents

EN 636:2012+A1:2015 

Plywood – Specification

This gives the requirements for plywood for general purpose use and for structural (load bearing) applications in dry, humid and exterior conditions. It also gives a classification based on bending properties.

Amendment 1 : 2015 makes the following modifications to EN 636 : 2012

a) The scope now clarifies that the standard includes overlaid and coated plywood, but it does not cover materials or processes used for overlaying or coating. Neither does it cover any materials or processes applied in relation to enhancement of biological durability.

b) Clause 12 Marking:

 (i) Panels marked within the European Economic Area for construction applications shall be marked according to EN 13986 plus

The number of this standard (EN 636) and the conditions of use:

EN 636-1 dry conditions

EN 636-2 humid conditions

EN 636-3 exterior conditions

 The letter corresponding to the panels intended application:

 “S” for structural (load bearing)

“NS” for general purpose (non-structural)

 The commercial name or botanical name of the wood species in the plywood

 (ii) Other panels – a new requirement to be marked giving the commercial name or botanical name of the wood species in the plywood.

 c) Annex B has been introduced giving guidance on the application of the use class system given in EN 335:2013 in relation to the biological agencies that can attack plywood. This useful guidance was originally given in EN 335-3:1995 but was removed when EN 335 -1, -2 and -3 were all merged into a single document, EN 335:2013.

It is important to note that some earlier modifications made to EN 636:2003 which appear in EN 636:2012+A1:2015 will not yet have been changed in EN 12369-2:2011.  This will occur when EN 12369-2 is reviewed in 2016.

These are:

a) New classes introduced to Table 1 EN 636:2012 for bending strength, F35: and Table 2 for modulus of elasticity, E35.

b) Changes to the lower limit values in Table 2 – modulus of elasticity.

The values listed in EN 636:2012+A1:2015 relate to product properties and are not characteristic values for use in design calculation. Such characteristics are given by the manufacturer based on testing and expression of results according to EN 789, EN 1058 and EN 1156. Values given in EN 12369-2 can also be used for characteristic values in design.

Definition of plywood classes for dry, humid and exterior conditions 

Biological durability

Plywood Class

Service Class Description

EN 636-1

Plywood for use in dry conditions.

Service Class 1 in Eurocode 5: – Plywood to be used in conditions characterised by a moisture content in the material corresponding to a temperature of 20°C and relative humidity of the surrounding air only exceeding 65% for a few weeks per year. Panels of this type are suitable for use in Class 1 of EN 335.

EN 636-2

Plywood for use in humid conditions including protected external applications. It is also capable of resisting exposure to the weather for short periods. Use in interior applications where the humidity rises above that given for dry use is also acceptable.

Servicer Class 2 in Eurocode 5: – Plywood to be used in conditions characterised by a moisture content in the material corresponding to a temperature of 20°C and relative humidity of the surrounding air only exceeding 85% for a few weeks per year. Panels of this type are suitable for use in Use Classes 1 & 2 of EN 335. This plywood is appropriate for protected external applications e.g. behind cladding or under roof coverings, but it is also capable of resisting weather exposure for short periods e.g. when exposed during the construction.  It is also suitable for interior situations where the service moisture condition is raised above the humidity of dry conditions.

EN 636-3

Plywood for use in exterior conditions including liquid water or water vapour in damp but ventilated locations.

Service Class 3 in Eurocode 5: – Plywood to be used in climate conditions leading to a higher moisture content than in service class 2. Panels of this type are suitable for use in USE Classes 1, 2 & 3 of EN 335. It is capable of withstanding exposure to weather conditions and liquid water or water vapour in a damp but ventilated location, under consideration of its biological durability.
  • For EN 636-1 plywood, the panels must be appropriate for the prevailing climatic conditions with the risk of attack being outlined in use class 1 of EN 335.
  • For EN 636-2 panels, the plywood must be appropriate for the prevailing climatic conditions. The risk of attack is outlined in use class 2 of EN 335.
  • For EN 636-3 plywood, the panel must be appropriate for the prevailing climatic conditions with the risk of attack being outlined in use class 3 of EN 335. In this use class, the performance will be compromised if suitable preservative treatment and/or relevant surface and edge coating is not applied and if the panels are not properly maintained and installed.
  • Guidance on the factors affecting durability and on precautionary measures which may be considered as necessary can be found in CEN/TC 1099

Other information

Other aspects of the panels properties also referenced in this standard deal with mechanical characteristics, formaldehyde release, bond quality etc. and the relevant European standards are given.  Details of factory production control and marking, identification and documentation are also covered.

An important aspect is the provision of a classification system based on the bending properties of the panel.  This system is independent of the panel’s composition factors. This tabulates values corresponding to the 5 percentile values for bending strength (F) and bending modulus (E). These are based on the mean values determined according to EN 310: Wood-based panels – Determination of modulus of elasticity in bending and of bending strength and EN 326-2 for individual panels and calculated in accordance with EN 326-1.

Four classes can be given in the sequence:

  • Strength in length direction
  • Strength in width direction
  • Modulus in length direction
  • Modulus in width direction

For example: F10/20 E30/40 (obtain values from the tables in clause 5 of EN 636)

These values cannot be used for structural design. They may be used with EN 12369-2: Wood-based panels – Characteristic values for structural design – Plywood, to obtain characteristic values for design purposes.



APA in Europe Wizard

All Questions OSBPlywood

What are the main changes to the FSC Chain of Custody Certification standard?

Download What’s New in FSC revised COC standard.   Also, the previous FSC compulsory verification programme has been replaced by a due diligence protocol with a new risk assessment system. Learn more.  North American good forestation practice supports the aims of EUTR.  Its sustainably managed forests comply with one or more of the five leading certification agencies responsible for verifying proper forestry practices.


Can US Underwriters Laboratories certified EPDs be used for environmental performance ratings under the BREEAM system?

Learn how APA products can count towards a building’s BREEAM rating.  The British Research Establishment and the US Underwriters Laboratories  now recognize each other’s certified EPD making it simpler for APA member mills to gain environmental performance ratings under the BRE Environmental Assessment Method  (BREEAM).

Does APA plywood meet the lowest category (E1) for formaldehyde release without need for further testing?

Under the harmonised European Standard for wood-based panels, EN 13986, Annex B, ‘wood-based panels glued with resins emitting either no formaldehyde or negligible amounts of formaldehyde after production as e.g. isocyanate or phenolic glue’ are to be classified as E1 (the lowest formaldehyde release class) without further testing.

See APA’s guide Formaldehyde and Engineered Wood Products.  APA plywood is designated under the lowest E1 category for formaldehyde release without needing further testing.  APA’s US PS 1 and PS 2 plywood have been tested to EN 717-1 and formaldehyde levels already meet the requirements for the E1 classification limit.

Also see:  Formaldehyde (plywood) and Formaldehyde (OSB).



Can APA plywood and OSB be used in non-construction applications?

US plywood and OSB are equally effective as sturdy, robust and cost-effective solutions  for non-construction applications – from shelving, site hoardings , protective linings in the cargo bay of delivery vehicles to packaging and furniture.   See APA’s Performance Panels.   Need help to decide what grade or type of panel to use for a specific application? APA’s Industrial Panel Selection Guide (Form T200) is another easy to use resource.

How do I equate product Use Classes with the Service Classes given in Eurocode 5 for the design of buildings using engineered wood products?

See APA’ s guide  to Service Classes and Use Classes. For maximum biological durability, both Service Classes and Use Classes must be considered when specifying US CE-marked panels .  This guide helps you make the right selection.


‘Hazard classes’ have been replaced (see updated EN 335:2013) by Use Classes covering plywood and OSB.  They will also cover LVL when the LVL standards have completed their current update.  Use Classes are based on different environmental exposures that can make the panel susceptible to deterioration. , as given in Eurocode 5, are used for assigning  strength values and calculating deformation in load bearing situations.  They are determined by the moisture content of the panel corresponding to the environmental humidity and temperature during service.

How do APA’s member’s products count towards a sustainability assessment for new construction or in refurbishment projects?

The British Research Establishment and the US Underwriters Laboratories  now recognize each other’s certified EPD making it simpler for APA member mills to gain environmental performance ratings under the BRE Environmental Assessment Method  (BREEAM).  This is the UK’s leading and most widely used environmental assessment method for buildings and communities. It sets the standard for best practice in sustainable design and has become the de facto measure used to describe a building’s environmental performance. Learn how APA products can count towards a building’s BREEAM rating.

What is a ‘life cycle stage’ and how do these link to the environmental assessment of whole buildings?

A good starting point is our Green Topics section and  Types of EPD and the five life cycle stages

How do core category rules link with environmental product declarations?

EN 15804:2012 +A1:2013 provides the core Product Category Rules (PCR) for the production of Environmental Product Declarations (EPD) for all construction products and services.  Review with main environmental standards.  For more details see: Core Product Category Rules (PCR) for Products and Services. 

Whose responsibility is it to check that wood products being imported into the EU do not originate from illegally sourced timber supplies?

The European Union Timber Regulation (EUTR) puts specific obligations on operators and traders . Operators (or importers) are any (natural or legal) person first placing timber on the EU market. They must maintain records of any traders that they supply timber to.  They must implement a due diligence system to minimise the risk of putting illegal timber or any of its derived products on the market.  Learn more.

Does the EUTR require mills to provide any extra documentation for customs entry into the European Union?

The European Union Timber Regulation (EUTR) puts specific obligations on operators and traders and applies to timber originating in the domestic (EU) market, as well as from third (non-EU) countries such as North America. The information it requires has to be retained for at least five years and be available on request.  See European Timber Regulation.

Must all plywood and OSB panels carry a CE marking?

Manufacturers of wood-based products  covered by either a harmonised European standard (hEN) or a European Technical Assessment (ETA) must apply for CE marking under the 2013 Construction Products Regulation.  See CPR & CE Marking  and our Official Guidelines section.

What is the definition of a construction product under the CPR?

This applies to any product or kit which is produced and placed on the market for incorporation in a permanent manner in construction works or parts thereof and the performance of which has an effect on the performance of the construction works with respect to the basic requirements for construction works.’

Products must clearly display the CE mark and have the correct Declaration of Performance documentation.  For more info: CPR & CE Marking.

What is a Declaration of Performance referred to under the Construction Products Regulation?

Under the CPR, manufacturers wishing to trade in the European market are legally required to set down the levels of performance for any construction product.  They have to be listed in an official document called a Declaration of Performance.

What is the difference between Structural 1 and Exposure 1?

Exposure 1 is a glue bond classification.  It uses the same 100% waterproof glue as exterior panels and refers to a panel’s durability when long delays in construction are expected or when facing high moisture content. For plywood, see  For OSB:

Structural 1 refers to a panel’s superior performance characteristics.  For OSB, see

For Structural 1 plywood,  all panels have special improved veneer grades and if manufactured to the American PS1 standard, the veneer grades will be species with a Group 1 strength classification.  See group classification of species.


The CE-mark on an APA plywood panel means it conforms to European Standards – but which ones?

Plywood Design Information looks at the plywood grades A-A, A-B, A-C; B-B, B-C; C-C, C-D and the relevant standards that the trademarked panels comply with.


I want to use a Rated Sheathing panel for flooring/ roofing application, what info do I need to know?

For plywood, see Span rating.  For OSB, see Span rating. A full range of technical information in under Products and Trademarks.

What extra strength benefits do Structural 1 OSB panels provide over standard Rated Sheathing panels?

OSB Structural I  on an APA trademark indicates that the OSB structural-panel meets the requirements of a Performance Rated panel.  This delivers superior design capacity for these panels over OSB Rated Sheathing and Sturd-I-Floor.  Also see Comparison of Superior Design Capacities for OSB Structural I Sheathing with OSB Rated Sheathing.

What is the difference between a touch-sanded panel and sanded panel?

Veneer in a finished US trademarked plywood panel must conform to one of the six grades listed in the US PS 1-09 standard: N, the highest classification (rarely produced), followed by A, B, C-plugged, C and D.  Non-overlaid APA plywood panels come in three levels of surface finish – sanded, touch-sanded and unsanded.

Also see veneer grades for Popular APA Plywood Panels.

How do APA veneer grades match those given in the European standards

APA has produced two easy to follow guides to help match the grade numbers given on a US finished plywood panel with the requirements of  EN 635-3.

Detailed guide listing permissible defects – with maximum sizes.

Simplified guide to the US PS 1-09 veneer grading rules and appearance grades in EN 635-3 based on the appearance of the surface veneers. Equivalents cannot be exactly compared as two different sets of grading rules apply.

How do I correctly gauge the face appearance a plywood Siding panel?

I want to specify an APA panel for concrete formwork – what do I need to know?

See APA’s comprehensive Concrete Forming Design/Construction Guide for architects, engineers and contractors and the types of APA concrete forming plywood panels.

Are APA panels tongue and grooved on all four edges?

APA panels have a tongue and groove profile on their two long edges.  This eliminates the need for support (blocking) under adjacent panel edges to prevent them from deflecting independently of each other when load is applied.  See Tongue & Groove  (plywood) and Tongue & Groove (OSB).

I am not familiar with the term ‘Sized for Spacing’ – what is its significance?

‘Sized for Spacing’ on APA Rated Sheathing, APA Rated Sturd-I-Floor and APA Rated Siding trademarks indicates that the manufacturer has produced the panel to a size slightly less than the traditional nominal 2440mm (96″) by 1220mm (48″).  It is done to facilitate proper panel spacing during construction.  See Sized for Spacing  (plywood) and Sized for Spacing  (OSB).  For further technical details see Product and Trademarks.

How are Performance Category and thickness related?

Performance Category, Panel Thickness and Span Ratings are key categories that need to be considered together.  See Thickness, Performance Category  (plywood) and Thickness, Performance Category (OSB).

I’d like to know more about a panel’s Span Rating and how it links to thickness.

Plywood: Span rating
OSB: Span rating

What is Span Rating on the APA trademark and why is it important?

Span Rating denotes the maximum recommended centre to centre spacing of supports in inches over which the panel should be placed with its strength axis across two or more supports. Plywood: Span rating.  OSB: Span rating

What is the difference between Exposure 1 and Exterior plywood panels? What are their appropriate uses?

Bond classification relates to moisture resistance of the glue bond and therefore to the structural integrity of the panel.  See glue bond durability classification (plywood) and exposure durability (OSB).

What are the main OSB panels likely to be available in Europe?

See APA’s guide to panel grades  and also info on understanding the trademark.

What are the main plywood panels likely to be available in Europe?

What are the main European standards that I would need to be aware of for OSB panels?

The main standards are: EN 13986 and EN 300.   But also see the other relevant standards for OSB.

What are the main European standards that I would need to be aware of for plywood panels?

The main standards are: EN 13986, EN 636, EN 314, EN 635-3.  And for more details, see EU standards for plywood.