Plywood is a panel product manufactured by glueing one or more veneers to both sides of a central veneer layer or a lumber-strip core. The development of plywood (as well as laminated and particle board) was made possible by the production of improved adhesives—especially synthetic resins—in the 1930s and ’40s. Most plywood is all-veneer; lumber-core plywood is produced only in small quantities. In both types of plywood products, the species, thickness, and grain direction of each layer are matched with those of its counterpart on the other side of the central layer. After the glue is spread, the panels are assembled and brought for pressing, usually in large, multistoried hot presses, where loading is automatic. Adhesives are thermosetting synthetic resins, phenol-formaldehyde is the most commonly used and urea-formaldehyde for plywood and can produce joints more durable than the natural wood itself and are thus highly resistant to weather, microorganisms, cold water, hot water, boiling water, seawater (“marine” plywood), steam, and dry heat. After pressing, the panels are stacked to cool and then sanded, graded, and stored. Plywood ranges in thickness from 4 mm for all-veneer to 32 mm for lumber-core.
Surface Veneer Grades for Pine Boards
(According to SABS Grade Requirements)
Plywood - B Grade (BB + BC)
B-Grade Ply is used in non-structural applications where a high quality aesthetic finish is required. This includes wall cladding and furniture making. When installed in areas with high damp, boards should be treated against fungal attack and should be surface finished with an appropriate sealer to minimize surface checking.
Plywood - C Grade (CC)
C-Grade or Shutterply is made of multiple thin layers of pine wood bonded together with an adhesive. Each layer is usually oriented with its grain running at right angles to the adjacent layer in order to reduce shrinkage and improve the board’s overall strength. Used primarily for concrete shuttering and mezzanine flooring.
Insulated truck bodies
Flooring in temporary housing, mezzanines
Plywood D Grade
D-Grade or Packing Ply is a lower grade of plywood used in applications where aesthetic appearance or durability is not a consideration. As such, packing grade boards are mostly used to construct boxes and crates used in the packing, storing and shipping of goods.
Plywood Film Face
Film Face Plywood boards are coated with wearable and waterproof film on both sides. The film is an adhesive-impregnated paper, which is different from melamine paper overlay and PVC. Its function is to protect the wood from moisture and weather, thereby extending its service life. It is suitable for use in shuttering and formwork.