Floor area (building) (FA) is a
building,
architecture, and
real estate term referring to the amount of area (measured as square feet or square metres) taken up by a building or part of it. The ways of defining "floor area" depend on what factors of the building should or should not be included, such as external walls, internal walls, corridors, lift shafts, stairs, etc. Generally there are 3 major differences in measuring floor area.