Engineered wood flooring is a composite material made of a filleted backing, a core of hardwood or plywood and a veneer wear layer, it is more stable in areas of fluctuating humidity and can be installed below grade (basements), you can also install radiant heating systems and install directly onto concrete or wooden substrates. Solid wood flooring is made from individual pieces of solid wood and should only be installed on a wooden subfloor, it is also recommended that you only install them above grade (upper floors) and avoid rooms with high humidity.