Jim Coulson on what exactly is marine plywood IN my first last article on plywood in CFJ December 2012, I attempted to explode the myth of the term WBP. This month I want to extend that myth-busting process to the other old chestnut which crops up with alarming regularity – those weasel-words, marine plywood! This name seems to be imbued with the same, almost magical properties that are given to WBP (weather and boil-proof) and therefore it suffers from the same problem. There is almost no proper marine ply in the UK; and most of the stuff that claims to be that is, in fact, nothing of the sort. It is almost a given that any plywood which has the name of marine ply is absolutely nowhere near the correct specification for that material – it’s that some less-than-scrupulous producer or shipper (or, dare I say it; importer…) has put that name to it, because that’s what the customer wants to see! But let me tell you straight: Unless it is manufactured to the exact requirements of BS 1088: 2003, then it absolutely is NOT marine plywood – no matter what people may call it on their sales literature. This British Standard was re-issued in a completely revised form in 2003, after being almost declared obsolete by BSI in the 1990’s: but the industry decided they wanted to keep it and so were told in no uncertain terms that they had to re-write it wholesale, to bring it into line with European norms. Therefore full BS 1088 marine plywood must have a number of definite things about it, if it is to correctly bear that name. 1 . It must be manufactured from timber species which have natural durability – that is, resistance to decay without preservative treatment. 2 . It must not have any manufacturing defects such as core gaps, overlaps, irregular veneer thicknesses and so on. (I described these in my second ar ticle). 3 . Most crucially, it absolutely must have a fully exterior glue-bond which meets Class 3 to BS EN 314-2, and 4 . To really be accepted as marine plywood it must be properly certified by an independent third-party testing house, which can vouch for its reliability. So if you are ever offered marine ply, ask these two questions of the supplier, before you buy it…. I Is it manufactured in accordance with BS 1088: 2003? And I Can I see a copy of the third party certificate or stamp, please? If it doesn’t have both of those – or if they can’t prove it to your satisfaction – then don’t buy it. Oh, and by the way, if it is marine plywood selling at less than about £25 a sheet (and more likely, £30 plus per sheet), then don’t say I haven’t warned you! Jim Coulson is a director of TFT Woodexperts T: 01765 601010 E: tft@woodexperts.com www.woodexperts.com This article has been reproduced from the Contract Flooring Journal website. You can find them at www.contractflooringjournal.co.uk.
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