Tip #127
Understanding Lumber Grades
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PLYWOOD GRADES

Plywoods are graded using a double letter designation such as A-A, A-D, etc. The first of these two letters designates the front or "face" side of the sheet, while the second letter designates the back side of the sheet.

Here is a description of each letter designation:

N: Made of selected, furniture or cabinet quality, all heartwood or all sapwood veneers. Intended for a natural, as opposed to painted finish. Free of all open defects with some repairs allowed.

A: A smooth surface which may contain some neatly-made repairs such as "footballs" and similar plugs. May be painted or in some cases, used with a natural finish in applications which may be less demanding.

B: Made with a solid surface veneer which may contain "footballs" and similar repair plugs, as well as un-repaired, tight knots. Best used for projects that are intended to be painted.

C: May contain sanding defects, as long as they do not negatively affect the serviceability or strength of the panel. Under certain circumstances, splits to 1/2" long and knotholes up to 1-1/2" are permitted.

D: This is the lowest grade plywood, typically used only for interior applications such as cabinet-backs and similar inner panels that will not be readily visible. D grade plywood may contain limited splits plus knots or knotholes up to 2-1/2" in maximum dimension and up to 1/2" larger in some cases.