All TTF members dealing in Marine Plywood products are required to comply with the Panel Products Code of Practice and specifically clause 2.2 which states that Marine Plywood supplied by Members is to meet the requirements of BS 1088:2003 (Marine Plywood). BS 1088 comes in two parts, Part 1 (Requirements) and Part 2 (Determination Of Bonding Quality Using Knife Test). The key requirements from part 1 of BS 1088 are highlighted in this circular. However, this is no substitute for purchasing and using the full version of the standard.

Requirements of manufacture include classification according to panel type, Standard (S) and Lightweight (LW). Standard marine plywood has veneers possessing outstanding durability with respect to fungal decay and bonding quality making it suitable for marine construction while lightweight marine plywood is of veneers from timber species of lower density/durability than those in standard marine plywood while all other requirements remain the same.

Standard marine plywood as defined in BS 1088 should have outstanding resistance to biodeterioration (durability) with time. The biological durability of marine plywood is expected to be greater than that of plywood of the same species that meets the requirements of BS EN 636-3. In this respect, Standard marine plywood should be made throughout of timbers having a durability rating of class 3, BS EN 350-2, or better and a nominal density of > 500kg/m3 and up to 5% sapwood per veneer is permitted.

According to BS 1088, Marine Plywood panels having a thickness of 6.5mm or less should have three or  more plies. Panels having a thickness of greater than 6.5mm should have five or more plies. With 3-ply panels, the combined thickness of the two outer plies after sanding should be between 40% and 65% of the nominal unsanded thickness of the panel. With 5-ply panels, the combined thickness of the two outer plies after sanding, combined with those of the core and other inner plies with their grain direction parallel to the outer plies, should be between 40% and 65% of the nominal unsanded thickness of the panel. Additionally, for panels with nominal thicknesses of greater than 3.8mm, each outer ply should not be less than 1mm thick after sanding and each inner and core ply should not be more than 4.8mm thick.

In accordance with BS 1088, all marine panels should not contain any of the following manufacturing defects: open joints (e.g. core gaps, overlaps and pleats, blisters, hollows, bumps and imprints), roughness (other than that due to the irregular structure of the wood), sanding through, foreign particles, defects in the edges of panels (e.g. due to sanding, sawing, missing wood).

All marine plywood as defined in BS 1088 should have outstanding resistance to loss of bond strength with time. When tested in accordance with BS EN 314-1, the bonding quality should meet a minimum requirement of BS EN 314-2, Bonding Class 3.