Plywood is made by gluing layers of wood veneer at right angle to one another. This results in the direction of grain in adjacent layers to be perpendicular to each other. Plywood is manufactured in odd number of layers such a 3 ply, 5 ply, 7 ply etc. The crossing over of the grain in each layer adds stiffness, strength and stability to the product. Suitability for outdoor use depends on the glue used in the manufacture of this product. Marine ply is often used in boat building.
PLYWOOD is an ecologically friendly engineered product whose finish quality varies considerably, some plywood have attractive grains while others can contain knots. Plywood is graded for exterior or interior use depending upon the water resistance of the glue used to stick the plies together.
Interior grade plywood does not contain water-resistant adhesive. It may be used for wall panelling, flooring and furniture.
Exterior grade plywood (WBP - Weather and Boil Proof) can be used outside. Water-resistant adhesives are used and can resist a certain amount of moisture. Sheds and cladding are made from this material. All Weather boiled proof plywood requires paint or varnish to protect the outer veneer from the elements. Shuttering boxes are made from shuttering plywood. Shuttering boxes are used in the construction industry to contain concrete while it sets. The material is water resistant to a certain extent. The surface of this material does not have a decorative veneer and is generally not suitable for use where an attractive quality finish is required. Marine Plywood is made with waterproof adhesive so that it can be used under water.
Plywood can be nailed and screwed. Thin plywood is flexible and can be formed into curved shapes.
Sizes: -Plywood is sold in 2440 x 1220mm and 1525 x 1525mm sheets. The most common thicknesses are 4, 6, 9 and 12 mm.