Glossary
GFA (Gross Floor Area)
Plain-Language Definition
The total floor area of a building measured to the external face of external walls, including all enclosed spaces on all floors, used as the primary measurement for regulatory, planning, and commercial purposes.
Technical Context
GFA calculation methods vary by jurisdiction and standard. RICS Code of Measuring Practice defines GIA (Gross Internal Area, measured to internal face of external walls), NIA (Net Internal Area, excluding common areas), and GEA (Gross External Area). BOMA/ANSI Z65.1 defines Rentable Area and Usable Area for office buildings. Key distinctions: GFA typically includes lift shafts, stairwells, plant rooms, and common areas but may exclude car parking, covered walkways, and balconies depending on the standard. Efficiency ratio (NIA/GIA) for offices typically ranges from 65-80%.
Why It Matters
GFA is the basis for building regulations (plot ratio/FAR compliance), property taxation, rental calculations, and performance benchmarking (EUI, cost per sqm). Inconsistent measurement methods between parties cause disputes in lease negotiations and property valuations. Understanding which measurement standard is being used is critical for accurate comparison.
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