Builders, contractors and environmentalists all like composite woods, which consist of wood fibers bonded together with adhesives and sometimes plastics or other materials. They can be stronger and more versatile than traditional lumber.
Composite wood also makes better use of trees. Almost every fiber in the entire tree can be used in composite wood, compared to about 40 percent that can be used for solid lumber. The main concern with composite wood is the addition of formaldehyde and other volatile organic compounds in bonding the wood fibers. However, manufacturers are finding alternatives to these unhealthy chemicals.
As traditional wood becomes scarcer and composite woods become safer, the range of options is expanding. Here are some of the types of composite wood on the market. A range of products is available under each broad category, and other categories also are available.
Plywood was perhaps the original composite wood. For roughly a century, manufacturers have been gluing together thin layers (or plies) of wood in alternating directions to make thin, strong boards that can be wider than lumber and more versatile.
A variety of other composite wood boards were since developed. Most use smaller fibers or chips of wood instead of layers of wood veneer. Particleboard can be made from wood waste, including wood chips, sawmill shavings and sawdust. It is widely used for making furniture, as is the heavier and stronger medium-density fiberboard. Known as MDF, it is one of several types of fiberboard made by fusing wood fibers to adhesives at high pressures and temperatures.
Structural Composite Lumber
After starting to replace thin wood boards, composite woods also began moving in on thicker structural lumber. Laminated veneer lumber, laminated strand lumber and oriented strand lumber are three common types of structural composite lumber. They differ in the grade and type of wood fibers and veneers they contain. However, they are all formed by layering wood and waterproof adhesive to form strong blocks.
Composite lumber is widely used for floor beams, headers and other spots that once required a traditional 2-by-4 or other lumber. It can be uniformly engineered, largely avoiding the threat of warping and splitting. It can also be formed into longer, straighter lengths than traditional lumber.
Another new composite wood option is showing up on outdoor patios. Composite decking blends wood and plastic fibers for a product that looks and feels like a wood deck, but can be expected to last longer with less maintenance than traditional wood decking.
Composite wood does not splinter or rot, will not shrink or expand, and it doesn't require annual sealing or other treatment. However, most composite decking still does not have the strength of wood and cannot cover as large a distance between support beams.
Plastic-wood composites are also used in landscaping, fences, window frames and furniture.
The range of composite woods includes plywood and other boards, a variety of structural lumber, and plastic-wood composites for decks and other projects.