How Plywood is Composed
Check out the differences between oriented-strand board and plywood.
Know Plywood Grades
- Fully waterproof bond (glue) between the layers and designed for applications subject to permanent exposure to weather and moisture.
- Exposure 1. Fully waterproof bond but not for permanent exposure to weather or moisture.
- Exposure 2. Interior type with intermediate bond. Intended for protected construction applications where slight moisture exposure can be expected.
- Interior applications only.
If you don’t have a lot of money and you don’t care if your plywood is baby smooth on the surface, go for a lower grade. It’s just as strong as the nicer looking grades.
- Smooth, paintable surface. Repairs to the veneer like replacing knots with patches can be made, but no more than 18. Used for projects like cabinets.
- Solid surface. Minor splitting permitted.
- Tight knots and knotholes allowed. Can also have discoloration and sanding defects on the surface as long as it doesn’t impair strength.
- Larger knots and knotholes permitted.
You’ll often see plywood with two grades as in “A-C.” This means that the face side is an A grade and the back side is a C grade.
In addition to the above two classifications, plywood is also rated as Sheathing, Stud I-Floor, and siding. This just specifies what a particular end use a piece of plywood was designed for. Most of the plywood you buy from the hardware store for projects around the house like a workbench will be classified as sheathing.