Grades:
Plywood grades are much more diverse when compared to OSB. Plywood is split into four main grades: A, B, C, D.
- A Grade: This is the highest quality. For projects that will be visible to the eye. Both sides of the sheet are smooth and easy to paint and are free from defects and knots.
- B Grade: Has characteristics similar to A grade, though will have minor imperfections and is slightly less smooth. This is considered the “standard” grade for most builders.
- C Grade: Has more visible flaws and knots up to 1.5 inches. More noticeable defects when compared to A and B grades.
- D Grade: This is your lowest grade of plywood. It could have large flaws and knots up to 2.5 inches and is unsanded.
Sub-Grades:
- Because plywood is a laminate, there are two sides that can be two different grades for 1 sheet. For example, an AB grade will have one side with an A rating and the other side with a B rating. The first letter refers to the grade of the face of the plywood, and the second letter refers to the back. An “X” signifies that this material can withstand some exposure to moisture. (As an example: CDX is a common grade for roof sheathing and has a C grade face, a D grade back, and is exterior rated).
