For LEED-CS projects, you need to determine the Core and Shell square footage (not the entire building square footage). This calculation is spelled out in the Building Owners and Managers Association (BOMA) standards as well as in the sample calculations

For LEED-CS projects, you need to determine the Core and Shell square footage (not the entire building square footage). This calculation is spelled out in the Building Owners and Managers Association (BOMA) standards as well as in the sample calculations in this LEEDuser strategy page. If the BOMA standard calculations determine that the Core and Shell building square footage is less than 15%, you are required to use 15% in the calculation rather than the actual percentage.