Hardwood Flooring Options on Concrete Subfloors

Solid Hardwood

• Solid hardwood flooring consists of planks made from one solid piece of wood, hence the name. With solid hardwood flooring, you can sand it and refinish it many times if you ever decide to change the look of your room without purchasing a new floor. However, you cannot install solid hardwood flooring directly over concrete; the moisture concrete produces will warp your wood over time. You also cannot install solid hardwood flooring below-grade (grade is ground-level), only above- or on-grade. Solid hardwood varies in thickness, although it typically ranges anywhere from three-quarters inch to five-sixteenths inch thick.

Engineered Hardwood

• Engineered hardwood flooring planks, not to be confused with laminate, consist of several layers of wood veneers. Sometimes the layers are different species of wood; sometimes they're all the same. Engineered hardwood flooring is stable and durable, partially because the different layers' grains all run different directions. This type of flooring doesn't fluctuate in size due to moisture as much as solid hardwood, making it the ideal hardwood for below-grade installation. Like solid hardwood flooring, you can sand and refinish engineered hardwood floors, although not as many times as solid hardwood flooring.

Choosing a Subfloor

• Plywood subfloors are the most commonly used. CDX tongue-and-groove plywood subfloor consists of thin sheets of veneer (typically southern pine) that are glued together to a thickness of five-eighths inch or three-quarters inch to form a 4-by-8 foot sheet. Oriented stran board consists of many wood chips glued together to form 4-by-8 foot sheets of varying thickness. Install three-quarter inch solid flooring over OSB, but add an additional three-eighths or one-half inch plywood before you install wood floors less than one-half inch thick.

Concrete

• For solid wood flooring, install a sleeper system over a plastic moisture barrier to put your floor on. The sleeper system consists of making joists with CDX subfloor attached to them over the concrete slab. For glue-down engineered flooring, perform moisture tests to ensure the moisture level of the slab stays at or below 4 percent throughout the year. The best option for concrete floors is engineered hardwood flooring installed over a plastic moisture barrier and the one-eighth inch thick underlayment.