Structural plywood is a strong, stiff, stable panel particularly suited for high performance flooring. The veneers are glued with heat and boil resistant Type A phenolic (exterior, marine) adhesive. Uses include house floors, garages, commercial floors, floors for factories, office, schools and other applications like stages, stadiums, truck decks, and transportable homes.
Ply Flooring (CD grade)
- Sanded surface C grade face
- Solid cross band for additional support of the face veneer, top 2 veneers are solid
- Can be used for flexible coverings like rubber, linoleum, cork tiles, thin tiles as well as rigid coverings
- Plastic tongue and grooved long edges, no nogging needed under edge joints, reduces squeaking
The C grade face may contain knots, filled holes or splits. As radiata pine is soft, the surface should be protected from indentation, paint spills, rust from steel strapping, steel nails, water damage etc where clear or stained finishes are required.
Ply Flooring and Ply Structural
Ply Flooring T&G sheets are made with a solid cross band veneer under the face. This provides extra support for high heeled shoes, fridge feet and the like, compared with standard edged Ply Structural plywood panels that are made with a D grade cross band under the face.
Use flooring when tongue and grooved edges are required to save the cost of blocking between the joints, and to reduce squeak problems.
Flooring plywoods are manufactured to comply with AS/NZS2269: 1994 “Plywood – Structural.” As such they carry Plywood Association Joint Accreditation System – Australia and New Zealand (PAA/JAS-ANZ) accreditation, stamps are on reverse of sheet.
Rain Wetting and Construction Time
Some material used in floors will not withstand exposure to weather. Untreated plywood will withstand rain and exposure during construction for up to three months. Some discolouration and minor checking of the surface can be expected if plywood is exposed for extended periods. For floors uncovered for long periods use H3 treated plywood to reduce the risk of decay. Return the plywood to less than 18% moisture content before installing moisture sensitive materials. Where a high quality visual finish is required, protect the Ply Structural or Ply Flooring plywood panels with a cover or sealer.
Wet Area Flooring
Floors in bathrooms, laundry spaces, kitchens and garages are exposed to water occasionally. Use H3 treated Ply Structural or Ply Flooring plywood panels where the exposure is likely to be regular or uncontrolled. For rental accommodation, motels and commercial residential floors, H3 treatment is recommended.
Preservative LOSP Treatment
Light Organic Solvent-borne Preservatives (LOSPs) are preservatives that contain combinations of fungicides and insecticides for timbers used in internal and external situations. All of these preservative components are incorporated in a solvent carrier such as white spirit.
LOSP treated timber may retain some of the solvent used in the treatment process for a period of time after treatment. The following precautions should be taken to minimise any potential health effects to users:
LOSP treated timber should be stored in a well ventilated, under cover area with any protective wrapping removed.
Where possible packs should be opened a day or two before use to allow any residual solvent vapours in the inner boards to evaporate.
Preservative CCA Treatment
Structural plywood is generally impregnated to H3.2 hazard class with CCA (Copper Chrome Arsenic) treatment to AS/NZS1604.3:2002. H3.2 hazard class is described as: “outside, above ground, subject to periodic, moderate wetting and leaching”. Refer to the standard for more detail.
CCA waterborne preservative is used for structural plywood. It has a green colour, and is dried following treatment so that the sheets may return to the correct dimensions and are at a moisture content suited to use in building. The fillets used to separate sheets in drying may leave marks on the sheet surface. These fade after a time, and are easily covered with paint but may be visible under stain.
The process of treating with CCA and subsequent drying is likely to increase the face checking of the panel.