Important defined terms for building classifications

Important defined terms for building classifications: A. First storey -- The uppermost storey having its floor level not more than 2m above grade. B. Grade -- The lowest of the average levels of finished ground adjoining each exterior wall of a building, except that localized depressions need not be considered in the determination of average levels of finished ground. C. Building height (in storeys) -- The number of storeys contained between the roof and the floor of the first storey. D. Building area -- The greatest horizontal area of a building above grade within the outside surface of exterior walls or within the outside surface of exterior walls and the centre line of firewalls.