Polyurethane flooring consists of a thick, poured layer of polyurethane resin, a plastic formed by organic units joined by urethane linkages. The poured layer forms a continuous surface.

Wood floors with polyurethane varnish do not count as polyurethane floors, as the layer of varnish is too thin, and the wood determines the main properties of the floor. Polyurethane is often used as a carpet underlay, although this does not change the flooring material categorization of a carpeted floor.

The polyurethane layer forms the exposed flooring. This separates it from epoxy or polyester floors, whose resin composition differs even when their continuous surfaces look similar.