External gross area is measured to the outside surface of the external building wall. Representing external gross area is not a requirement for working with the Space domain. Draw this area if you plan to track building efficiency and construction cost comparison.
The external gross area is measured to the outside finished surface of the permanent outer building wall, disregarding cornices, pilasters, and buttresses that extend beyond the building wall face. The external gross area of a floor is generally fixed for the life of the building and can only be changed with major building renovations.
See Also