Solid wood planks are milled from a single piece of hardwood and covered with a thin, clear protective layer that often consists of aluminum oxide, ceramic or an acrylic substance.
Typically three quarters of an inch, the thickness of solid wood planking enables it to be sanded and refinished many times throughout the life of the floor.
Because the plank is a solid piece of wood, it will expand and contract in accordance with the home’s relative humidity. To prevent warping, the home’s interior relative humidity needs to remain between 45% and 65% all year round.
Solid wood flooring is available in a wide array of wood species—including oak, maple, and black walnut as well as regional-specific choices like pecan, mesquite and others. The market also sometimes offers exotic species of hardwood from Brazil, Africa and elsewhere.
Hardwood planks classified as “engineered” feature multiple layers (typically three to five) bonded together under extreme heat and pressure.
The layers typically include a top veneer of hardwood backed by less expensive layers of plywood—although some manufacturers use substrates made from recycled wood fibers mixed with stone dust for improved durability and stability.
Because of the way engineered hardwood is processed, it is not as affected by humidity as solid wood planks are. Therefore, the product is often the preferred choice for kitchens and bathrooms or in areas where the humidity level can vary—like in a basement or a part of the house below grade, as long as a moisture barrier is placed between the subfloor and the hardwood planks.