Gross internal floor area (GIFA), or internal area, is the total floor area of a building measured internally, in accordance with IPMS 2 (internal) under the International Property Measurement Standards.
IPMS 2 measures each floor to the internal dominant face of the external walls, and includes internal walls, columns, circulation and plant areas. GIFA is the standard basis for expressing building costs in the UK: NRM 1 cost plans and most benchmark data quote costs per m² of GIFA, so an accurate, consistently measured figure is essential. The traditional gross internal area (GIA) under the RICS Code of Measuring Practice is measured to the internal face of the perimeter walls, so the two bases can give slightly different results.
- Always record which measurement standard has been used.
- Recheck the GIFA at each design stage, as small changes affect every rate per m².
Related terms: Gross External Floor Area, Net Internal Area, Cost per m², IPMS.
