Solid hardwood floors come in a wide range of dimensions and styles, with each plank made of solid wood and milled from a single piece of timber. Solid hardwood floors were originally used for structural purposes, being installed perpendicular to the wooden support beams of a building. Modern construction techniques now rarely use wood building frames and solid hardwood floors are used almost exclusively for their appearance.

For flooring, solid wood has many limitations due to the natural characteristics of wood. Expansion and contraction of wood from moisture and temperature fluctuation puts many dimensional restrictions on solid wood floors. Typically, 5" wide and 3/4" thick boards are the largest that can be manufactured from solid wood without compromising the structure of the flooring (some manufacturers produce wider boards using proprietary milling techniques). There is, however, no standard size which will perform well in every environment. For contemporary construction techniques, the most significant characteristic of solid wood floors is that they are not recommended to be installed directly over concrete.