There is a vast array of wood types and products when it comes to choosing wood floors. Once moisture issues are resolved in the design process, wood flooring can be suitable in all kinds of different areas, including below grade or concrete slabs. The two main types of wood floors are Engineered and Solid.
Known for retaining its dimensions over a wide range of environmental conditions, engineered wood can have advantages over solid wood for some applications. If you're looking to avoid potential shrinkage and gaps, engineered wood is a good choice. Also, because it's more dimentionally stable, due to the cross-lamination of each layer, it can be installed as a 'floating' floor, including over concrete, radiantly heated subflooring, or other surfaces where a nailed-down solid floor may not be practical. There are hundreds of engineered floors on the market, some with thicker 'wear-layers' that can be sanded and refinished in the future, as needed, just like their solid counterparts.
Solid wood has served as the floor of choice for hundreds of years, due to its durability, beauty, andavailability as a (factory)pre-finished or unfinished product. Because of its 'wear-layer', both pre-finished and unfinished products can be sanded and restored many times, with options to change color or stains. Solid wood adds structural integrity to your home. When installed conventionally, which is perpendicular to the joists, hardwood floors provide more stability to the entire floor framework and help prevent vertical deflection (bounce) in the floor. Moreover, most realtors agree that homes with hardwood floors have increased re-sale value!