Understanding plywood

Plywood is ideal for applications in residential and light-duty construction and is made from thin sheets of veneer that have been peeled from debarked wood. These thin layers,are glued together in alternating, perpendicular directions to create a cross-graining pattern. This pattern results in added strength and stability that resists shrinkage and expansion, should it come in contact with moisture.

This guide will walk you through the different uses of plywood, as well as explain its rating and grade system.


Plywood is a popular choice in construction because of its low cost. It is usually used in areas that are hidden from view in a post-construction capacity.

The most common uses for plywood include support for floors, walls, roofs and garages in residential construction.

Grades & Sizes

Plywood is sold in various grades and sizes. Make your selection based on the type of project you’re working on.


Four grades of plywood: A, B, C and D. A is the best and most expensive, and D the least expensive.

A-grade plywood features a smooth, sanded surface without knots. Any wood defects have been repaired with synthetic filler, so the veneer can be painted, making it ideal for furniture or cabinet doors. B-grade plywood also features a smooth, sanded surface, but may have more repaired defects up to 1-inch across.

C-grade is unsanded and may have several minor defects that will need to be repaired with knots up to 1 1/2 inches across, discoloration and sanding defects.D-grade is also unsanded with defects that have not been repaired and knot holes up to 2 1/2 inches across, discoloration and sanding defects.

You may also find ratings with two-letter classifications, such as BC. BC-grade is a mix grade plywood with one side graded a B, while the other side is graded a C.


The most common size for plywood sheets is 4 x 8 feet, followed by 5 x 5 fee.These project panels help eliminate waste, cut costs, and are easier to transport than full-size panels.

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