A flooring material that looks like solid wood may actually be a product known as engineered hardwood. Engineered hardwood doesn't give away its identity easily, especially when you use it as a floor covering. From the surface, it looks just like oak, maple, mahogany or a more flamboyant or exotic hardwood. It wears just as well as hardwood, and you install it the same way. Underneath its showy veneer, though, is a simple, relatively inexpensive core made from softwood or fiberboard. Engineered boards are an answer to dwindling hardwood supplies—especially exotic species—but they are more than that. In many cases, engineered boards are an improvement on solid hardwood, and you can use them in places that solid hardwood can't cut it. For the budget-conscious, it doesn't hurt that engineered hardwood is usually less expensive than its solid hardwood counterpart.
Quality of Engineered Flooring Boards
Engineered wood products already have a long history in residential construction and have found its way into all aspects of the building trades, from siding to structural lumber to subfloors. Plywood is familiar to anyone who has ever swung a hammer or wielded a saw, and modern builders have access to glue-lam beams and even two-by-fours made from laminated bamboo strands. When you hear the phrase "engineered wood," though, the term usually refers to flooring boards.
Like plywood, engineered flooring boards are usually constructed in layers. The top layer is a hardwood veneer, and the core is constructed either of layers of softwood glued perpendicular to each other or of high-density fiberboard (HDF). Both types of cores give the boards more resistance to swelling and shrinking than solid hardwood. Veneer thicknesses range from 0.6 to 6.0 mm (1/32 to 1/4 inches), depending on the method used to produce the veneer. Boards with thicker veneers have characteristics more like solid hardwood and last longer, but those with thin veneers require fewer raw materials and are less expensive. Manufacturers use one of three methods to cut veneers:
- Dry-sawing: Boards are allowed to dry, then are sliced into strips with a bandsaw or table saw. The veneers produced by this method are the thickest and most expensive and have the same grain pattern as solid boards.
- Rotary peeling: Logs are soaked until soft that placed on a rotary device similar to a lathe. As each log spins, a sharp knife peels a thin, continuous layer. This produces relatively thin veneers with repeating grain patterns like those on plywood.
- End peeling: Logs are softened by soaking, then the ends are peeled with sharp knives and pressed into veneers. This method creates the most veneer material from a single log, and the veneer is more structurally stable than that produced by rotary peeling, although it has less resemblance to solid hardwood.
Engineered flooring boards may also be impregnated with a liquid acrylic, such as methylmethacrylate (MMA), to increase stability and make color more uniform. Whether or not boards have undergone this process, they are almost always coated with an aluminum oxide or a similarly durable factory finish. Unfinished engineered flooring is available, but it isn't common.
Pros and Cons of Engineered Hardwood
Many homeowners opt for engineered flooring over solid hardwood based on cost, and while it's true engineered boards tend to cost less, the price difference depends on the quality of the product. The cost of manufacturing high-quality engineered flooring renders the final price of the product comparable to that of solid hardwood. Besides cost, several other factors enter into the choice between engineered and solid wood. Some of the benefits include:
- Structural stability: The laminated or HDF core gives engineered hardwood more stability than that of solid boards. Boards don't swell or shrink as much, so cupping and gapping occur less frequently. Because of this stability, engineered boards can last in places that solid boards can't, such as on concrete pads and in basements.
- Ease of installation: You can buy nail-down engineered boards that require exactly as much effort to install as solid ones, but you also have the option of purchasing snap-together boards that require no nailing or gluing. Add to this the fact that engineered boards come complete with a durable finish that eliminates the need for you to sand and finish, and you have an installation process that can take significantly less time and expense.
- Environmentally friendliness: Because a veneer requires a fraction of the raw materials expended on producing a solid hardwood product, it conserves resources. The raw material needed to produce a batch of solid hardwood boards can produce four times as many engineered boards. This is an important conservation in an era in which many exotic species have been over-harvested and have become rare.
These pluses notwithstanding, engineered flooring boards have a few drawbacks that are important to consider when deciding to use them. Most drawbacks are associated with less-expensive brands.
- Thin veneers: If you purchase a product with a veneer thinner than 1/16 inch, you won't be able to sand and refinish the floor. The factory finish is durable enough to provide 20 or more years of service, but when it wears out, or an accident occurs, you'll probably have to replace the floor.
- VOCs: The laminating glue in cheaply made engineered hardwood may contain formaldehyde, which has been linked to various forms of cancer. Most products sold in the U.S. are tested for this harmful chemical, and some budget unfinished flooring produced in China has been found to emit levels of VOCs (Volatile Organic Compounds) that exceed safe limits. Stay safe by avoiding cheap or unfinished materials.
Installing Engineered Hardwood
Many engineered products are milled exactly like solid ones. They have a tongue and groove that fit together, and you nail them in place in the same way you nail solid boards. Some engineered products, however, have locking mechanisms like the ones on laminate flooring planks, and you install these boards by simply snapping them together. This is a boon for any homeowner wanting to install the floor as a DIY project.
Even though engineered boards are less responsive to moisture changes, they still need moisture protection, so before installing them, you should cover the subfloor with a moisture-resistant barrier. It's also important to level the subfloor, because even small bumps or depressions can create gaps between boards and even cause cracking. Before you begin installation, plan the board direction to harmonize with the dimensions of the room. The general rule is to lay the boards parallel with the sightline from the main entrance, but other factors, such as placement of prominent features like the fireplace and direction of the floor joists, also enter into it.