Which term refers to the total square footage combining net area and nonassignable area?

The term that refers to the total square footage combining net area and nonassignable area is Gross Building Area. This metric includes all of the spaces within a building, encompassing usable spaces (net area) and the spaces that serve the building but are not assigned for specific functions, such as corridors, restrooms, and mechanical spaces.

Understanding Gross Building Area is crucial for architects, as it helps in determining the building's overall size and estimating costs, as well as compliance with zoning regulations and building codes. The concept of combining net and nonassignable areas enables a clearer picture of the building's entire footprint and the space available for different functions.