Traditionally, hardwood flooring came in thick planks of solid timber. Today, solid hardwood is still widely available, but many companies may also offer engineered flooring—planks made with a thinner top layer of hardwood, bonded to other layers and designed to prevent the floor from shifting during expansion or contraction cycles.
For basements and flats with concrete subfloors, engineered flooring provides an installation advantage. Whereas solid wood is generally installed over one or two layers of plywood, which can raise the height of a floor and interfere with existing doors or marginally reduce ceiling height, acting as a disadvantage.
But choose carefully because some engineered floors have top layers so thin that they can’t be sanded and refinished in the future.