Building Grossing Factors. GSA uses a number of standard building grossing factors for
establishing space "budgets" which are used for setting construction cost budgets for U.S.
GSA recognizes that U.S. Court building designs require more public space than do other
federal office buildings. Allowances for this public space and additional circulation systems
are included in the building grossing factors assigned to U.S. Court projects.
For U.S. Court projects, GSA charges designers with developing building designs for U.S.
Court facilities in which at least 67 percent of the total "gross" area of the building is
"occupiable" space as defined in the FPMR. The calculation of this efficiency shall be done
as shown on GSA Form 3596, Project Development Cost Estimating Requirements for New
Construction. This document shows that the total efficiency is a weighted average of all the
space types in a building. The 67 percent minimum efficiency for courthouses is the total
occupiable area minus interior parking, divided by the total gross space, minus that portion of
the gross applicable to interior parking, which is not necessarily an entire floor if there are
other functions on it. The gross area includes mechanical and service spaces on mezzanines.
To help clarify these definitions, the following diagrams illustrate two conditions (office floor
and courtroom floor) typical of many U.S. Court facilities. The diagrams illustrate the total
"occupiable" and "gross" areas provided on each floor.
April 5, 1996