Young Brunette Girl Near Stairs On The 2nd Floor

Floors typically consist of a subfloor for support and a floor covering used to give a good walking surface. In modern buildings the subfloor often has electrical wiring, plumbing, and other services built in. Because floors meet many needs, some essential to safety, floors are built to strict building codes in the first world.
Special floor structures
Where a special floor structure like a floating floor is laid upon another floor then both may be referred to as subfloors.