Technical Data

Plywood Face Grade

Plywood grades are largely determined by veneer quality on the face and back. The first letter designates quality of face veneer (better side), while the second letter denotes the quality of the back of plywood. B/C means one side B grade the other side C grade.

The letter “X” indicates the panel was manufactured with scrap wood as the inside plies, not “exterior” as is commonly thought.

The A-D rating is only good for construction (softwood) plywood, not for hardwood plywoods such as oak or maple.

“A”: Highest grade quality available. Can be defect free or contain small knots, providing they are replaced with wooden plugs or repaired with synthetic patch.

“B”: Second highest quality veneer grade. Normally a by-product of downgraded “A” quality veneer. Solid surface, but may contain small diameter knots and narrow surface splits.

“C”: Considered to be a lower end face quality, but a reasonable choice for general construction purposes. May contain tight knots and manufactures may repair the defects with synthetic filler.

D”: Considered to be the lowest quality veneer and often used for the back surface for construction grade panels. “D” grade veneers are neither repaired and is not recommended for permanent exposure to weather elements.

Plywood With Different Bonding

Interior Plywood: Plywoods for interior use only are made from various hardwood and softwood species, and can be used only in interior applications such as wall sheathing, furniture (where exposure to moisture is limited), cabinetry and the like. Interior plywood is available in most grades, as well as a number of hardwood species such as birch, oak and cherry.

Exterior Plywood:  The glues used in exterior plywoods are much more moisture resistant than interior plywoods. Once again, nearly all grades are available, with A/C, B/C and CDX the most common. Numerous hardwood species are also available in exterior varieties.

Marine Plywood: When moisture resistance is a priority, look into marine plywood. This type uses the best adhesives and is manufactured to the highest standards. It also is most commonly graded as A/A.

Structural Plywood: When the appearance of the face is of lesser concern than the strength and stability of the material, structural plywood will typically be the choice.