information/FAQs

Plywood bond types

Australian Standards define and specify tests for four types of glue bond:

Type A bond is produced from phenol formaldehyde (PF) resin that sets permanently under controlled heat and pressure and will not deteriorate under wet conditions, heat or cold. It is readily recognised by its black colour.

The Type A bond is specified in AS/NZS2272 for marine plywood, AS/NZS2269 for structural plywood, AS/NZS4357 for structural laminated veneer lumber and AS2271 for exterior plywood used under conditions of long term full exposure or under wet or damp conditions. The PAA Product Certified exterior, structural and marine stamps are applied to Type A bonded plywood.

Type B bond is produced from melamine fortified urea formaldehyde resin (MUF) which again sets under controlled heat and pressure. Type B bond is included in the exterior plywood standard for applications involving up to two years maximum exposure such as formwork plywood or plywood used in semi exposed applications such as exterior door skins. Type B bonded plywood is branded with the PAA Approved B bond stamp.

Type C and Type D bonds are both interior bonds and are not recommended for any purpose where exterior use or wet or damp conditions are involved, or where long term load bearing requirements exist. The glue line is light coloured.

Type C and D bonds are produced from urea formaldehyde resin (UF) which also sets under controlled heat and pressure. Type C and D bonds are specified in AS2270 for interior plywood and are suitable for interior non-structural applications. Types C and D bonded plywoods are branded with the PAA Approved interior stamp.

Only phenolic glued Type A bond plywood is recommended for areas of doubtful moisture conditions, such as areas around sinks, vanity units and laundry tubs.

Reference: Plywood Association of Australia brochure "Featuring plywood in buildings"