midfloor

Midfloor is an architectural term referring to an intermediate floor level within a building, situated between two principal floors. Unlike a full floor, a midfloor may be a mezzanine, gallery, or platform that does not occupy the entire footprint of a story or may have a reduced floor-to-ceiling height. Midfloors are used to gain additional usable space for functions such as offices, storage, mechanical rooms, or circulation without adding a complete level of height to the exterior envelope.

Location and form vary by project; some midfloors extend across the full footprint but with partial height sections, while others cover only part of the floor area. In parking structures and industrial facilities, midfloors can serve as intermediate levels between main decks.

Construction and design considerations include structural support for the added load, vertical circulation (stairs and elevators), fire safety and compartmentalization, vertical penetrations, HVAC, and daylighting. Accessibility must comply with local codes. In some regions, mezzanine is the more common term for such spaces; 'midfloor' may be used to describe a level that is between full floors but not a mezzanine per se or may be used interchangeably depending on local practice.

See also: mezzanine, intermediate floor, platform, floor.