Structural Plywood - Getting it Right
In the UK plywood is amongst our oldest man-made construction products, characterised by fitness for purpose and reliability. While there are many types and grades of plywood available in the UK today, imported from many countries - North and South America, Europe, Scandinavia and the Far East - only certain types and grades, from certain countries, are currently deemed suitable for structural use in the UK.
The issue of appropriate plywood for structural use has been "live" for some time now, with a growing consensus about the need to educate those involved in the specification, supply and purchase of structural plywood in the UK - and to stamp out the use of unapproved plywood.
Bruce Muirhead, President of the Scottish Timber Trade Association (STTA), many of whose members are involved in the importation and supply of structural plywood, is very clear on the position. He says:
"It is vital that we in the timber trade recognise the importance of this issue. If the wrong grade of material is supplied and subsequently suffers structural failure, timber as a whole loses market share. And ignorance of end use is no excuse: STTA members are clear that as suppliers we share responsibility with specifiers and purchasers to check end use so that the correct grade can be supplied".
Mr Muirhead adds:
"There are of course many applications such as site hoardings, packaging etc. where the use of less costly non structural plywood is adequate. The responsible supplier must however ensure that the customer is aware of the right grade for the job - and that the customer does not choose just on price. Where non-structural plywood is supplied, documentation from the supplier must make this clear."
Summarising the STTA's stand, Bruce Muirhead says:
"Plywood is an excellent material - it's versatile, reliable and predictable and it offers a guaranteed performance. We in the STTA want to see responsibility for the use of appropriate plywood for structural applications taken by all the sectors involved: designers and specifiers; importers and merchants; buyers and site staff."
Choosing the right plywood for structural applications is, however, easier than you might think. Here are some pointers which will help to "get it right"- ensuring that the correct type and grade of plywood is used:
Plywood for structural use in the UK is described in BS5268: Part 2. Such plywood is manufactured under the auspices of independent third party quality assurance programmes providing assurance of the physical characteristics and properties of these products. If it isn't in BS5268: Part 2, or alternatively does not have an Agrement Certificate, then it is not for structural use in the UK.
BS5268: Part 2 also requires that every sheet of plywood recommended for structural applications is clearly marked with the appropriate structural plywood grade mark. Examples of these grade marks are given in BS 5268: Part 2. If a sheet of plywood isn't marked with the appropriate grade mark then it is not for structural use in the UK.
BS5268: Part 2 lists only certain types and grades of plywood produced in Canada, Finland, Sweden and the USA as appropriate for structural use in the UK. It should be noted that only certain specified grades from each of these countries are permitted for structural use - see BS5268: Part 2- and that the correct grade must be specified for each application. BS5268: Part 2 also provides essential design guidance and design data for specified plywood types and grades.
t is also possible for products to demonstrate that they meet the requirements of Building Standards/Regulations through product conformity certification from the British Board of Agrement (BBA).
The situation for suppliers and specifiers is thus straightforward: anyone who uses any of the plywood products listed in BS:5268 Pt 2 can be confident that the product will, without question, meet current requirements for structural plywood, as long as the correct thickness is specified and used. Similarly, with the same provisos, plywood products with BBA certification can be specified and supplied with confidence.
Information and Advice - If in doubt, ask!
Information and advice to specifiers and users is readily available from various sources, and the message from the STTA is "If in doubt- ask!"
Experts in this area include the Timber Trade Federation (TTF) 0207 839 1891, the Scottish Timber Trade Association (STTA) 01786 451623, TRADA Technology Ltd (TTL) 01786 462122, APA-the Engineered Wood Association, 01202 201007 and CANPLY, The Canadian Plywood Association (formerly COFI), 01252 522 545.
In addition, the Timber Trade Federation's National Panel Products Division (NPPD), has circulated a list of the types and grades of plywood which are listed in BS5268: Part 2 as being for structural applications or which have an Agrement Certificate to this effect. (Click here for Structural Plywood Grading Tables for American, Canadian, Finnish, and Swedish grades.)
The Way Forward - Buying with Confidence
The NPPD is producing a Code of Practice which all TTF members (including, of course, the STTA), who deal in panel products, will be required to adopt, comply with and display. (Full text of the NPPD Code will be available as soon as possible on this site).
The aim is to ensure that specifiers and users of structural plywood can "buy with confidence" from TTF/STTA members who, as signatories to the Code, are committed to selling all panel products with accurate and precise descriptions and with the appropriate advice.
In conclusion, Bruce Muirhead says:
"We in the STTA are committed to ensuring that the right plywood is used for structural applications, where reliable performance is of prime importance. We have the products and the expertise necessary to help specifiers and users of structural plywood to "get it right" - and that's what we are committed to doing."