Along with framing lumber, trim, and drywall, you may find uses for different types of sheet stock. This category includes plywood, particleboard, oriented strand board (OSB), medium-density fiberboard (MDF), and medium-density overlay (MDO). These products come in 4x8-foot sheets, in thicknesses from 1/8 to 1-1/4 inches (although the thickest and the thinnest sizes may be harder to find). Along with full sheets, many home centers offer quarter and half sheets.
With all these options, it can be difficult to choose the right sheet stock for your project. We'll help you navigate the wood aisle by explaining the different types of sheet stock, showing you how to read a plywood stamp, and providing important tips for moving sheets.
Types of Sheet Stock
- Plywood, an engineered wood product, is made of a sandwich of thin layers of wood called plies, or veneers. Each successive ply is laid with the grain running at 90 degrees to the previous layer. The resulting sheet is dimensionally stable and very strong.
- Construction plywood, made of softwood veneers, is graded according to the quality of the veneers that make up the two outside faces. These grades, from best to worst, are A, B, C, and D. One of the most common grades of plywood used in construction is CDX, meaning the sheet has one face graded C and the other D. The X stands for exterior, referring to the glue that bonds the veneers. Builders use this grade for sheathing and roof decking. AB plywood, a better grade of plywood, is a good choice for shelving and utility cabinets.
- Hardwood plywood is faced with hardwood veneers and is used primarily for furniture and cabinetry. Home centers usually carry oak and birch veneer plywood. If you want another species, such as cherry, you can order it through a home center or contact a plywood distributor (look under "plywood" in the phone directory).
Other sheet goods are not as recognizable as wood, although they are wood products.
- Particleboard is made of coarser wood particles. It is commonly used as floor underlayment and occasionally for inexpensive cabinets (often with a vinyl wood-print veneer). It also is frequently used as the bottom layer for countertops.
- OSB, another engineered sheet made of bigger pieces of wood, is stronger than either MDF or particleboard, although not as strong as plywood, and is commonly used for sheathing and roof decking.
- MDF is made of fine wood fibers that have been pressed and glued together. The resulting sheets are very smooth and flat. MDF paints well and is a good choice for interior shelving and painted cabinetry.
- MDO has a paper face designed to take paint beautifully. It is commonly used to make outdoor signs.
How to Read the Plywood Stamp
When shopping for construction plywood, look for a grading stamp that says "APA The Engineered Wood Association." This stamp's meaning varies according to the intended use of the panel. For example, if the plywood is graded for sheathing outside walls, it will include the stud spacing on which it should be attached. For interior remodeling, the appearance of the face veneers is most important. Here are the characteristics of each face grade:
A — A smooth, paintable veneer free of knots and possessing only neatly made repairs that are parallel to the grain. It can be finished with a clear coat (rather than paint).
B — A solid-surface veneer that allows only small round knots, patches, and round repairs. Acceptable for the inside surfaces of a painted shelving unit.
C — Allows small knots, knotholes, and patches. Probably not used for an exposed face inside the house unless you are going for a rustic look. The lowest grade allowed for permanent exterior exposure.
D — This veneer can include large knots and knotholes. Acceptable only for a hidden face, such as the surface of a sheathing panel that faces inside the wall.
How to Carry Plywood
Sheets of plywood aren't very heavy, but carrying them can be awkward because of their 4-foot width. A panel carrier, which hooks under the sheet and extends your reach, gives you better control and helps prevent back strain. The tool is available at home centers and hardware stores.