Particle board: Review specs for the lowest-cost engineered wood panelsParticle board-the most economical form of fiberboard-is suitable for flooring underlayment and cabinetwork that will be finished with plastic laminate or wood veneer.

Particle board is an engineered-wood panel product that's made primarily from recycled waste wood. (Interestingly, about 75 percent of the particle board manufactured in the U.S. and Canada is made entirely from recycled materials.) Manufacturers take sawmill shavings, wood chips, saw dust and cut-off lumber pieces, grind them up into fine particles and mix them with a synthetic resin or other binder. This wood-chip slurry is pressed and heat-cured to create large, flat, hard sheets.

The three most common resins used to make particle board include:
• Urea formaldehyde, a popular, inexpensive, easy-to-use resin that's commonly used to produce non-water-resistant panels.
• Melamine formaldehyde, a more expensive resin that's used to make moisture-resistant particle board.
• Phenol formaldehyde, an expensive, very durable, dark-colored resin that's usually mixed with other additives to increase the particle board's resistance to moisture, fire, or insects.

Note that all commonly used particle board resins contain formaldehyde, a suspected carcinogen. Be sure to wear a respirator whenever you cut or machine particle board to avoid inhaling the dust.

Particle board is less expensive and denser than plywood, and is occasionally substituted for plywood when appearance and strength aren't critical. And although particle board can be machined, it's not as machinable as MDF, which is much denser, smoother and stronger than particle board. Particle board is most often used as a substrate for plastic laminate, melamine or wood veneer. Major particle board manufacturers include Boise Cascade, Collins Products, Georgia Pacific, Temple-Inland, and Louisiana Pacific.

Particle board: Sheet Sizes and Thicknesses
Stanard particle board sheets measure 4 feet wide by 8 feet long. Sheets up to 5 feet wide and 12 feet long are also commonly available. And most major manufacturers will custom-make particle board sheets to your specifications.

Particle board is available in thicknesses ranging from 3/8- to 1- 3/16 inches, although a vast majority of sheets sold are 3/4-inch thick.

Particle Board: Basic Applications
In the homebuilding industry, construction-grade particle board is commonly used as a subfloor, and particle board stair treads are sold in most markets (see Specialty Products below). When used as a subfloor, particle board is often laid over a plywood or solid-wood deck. Note that particle board is susceptible to edge swelling and other moisture-related problems, so it should be protected from the weather at all times.

Construction-grade particle board is made with slightly larger chips and, as a result, has a slightly rougher surface. A finer grade of particle board, which is made from tiny wood chips, is denser with smoother surfaces; it's often used as a substrate for plastic laminate, melamine, wood veneer or paint. Graded-density particle board is a fine-grade sheet that contains coarser-grade wood particles at the center and increasingly finer particles toward the surface, resulting in a very smooth, hard sheet.

Because it's constructed primarily of wood chips, great care must be taken when driving fasteners into the edges or close to the edges of particle board. Using too large a fastener or not boring pilot holes will split the sheet or fracture the surface. Particle board can be bonded using a wide range of woodworking glues and construction adhesives. Contact cement is typically used to adhere plastic laminate.

Although coarse-thread drywall screws and decking screws can be used to fasten particle board, a better option is particle board screws, which have deep, coarse threads and super-sharp points.

Specialty Products: Particle Board Stair Tread and Shelving
Besides large sheets, two precut particle board products are commonly available: stairtreads and shelving. Particle board stairtreads are designed for use on staircases that will be covered with carpeting. The 1-1/8-inch-thick-by11-1/4-in.-wide tread stock is available in lengths ranging from 6 to 12 feet, so it can be field-cut to fit. Particle board stair tread has a bullnose profile routed along one edge.

Precut particle board shelving comes in a wide variety of sizes ranging from 8 to 12 inches wide and in lengths up to 8 feet. The 3/4-in.-thick shelving comes unfinished or covered with white melamine along one edge and both top and bottom surfaces.

Additional Resources
Composite Panel Association