Building footprint

Hi all, I have read your definition of building footprint (Building footprint is the area on a project site used by the building structure, defined by the perimeter of the building plan. Parking lots, landscapes, and other nonbuilding facilities are not included in the building footprint) but I have some questions. My proyect is composed by 3 buildings. The buildings are not jointed at ground floor but they are at first floor. My doubt is if the building footprint should include the projection of the first floor or if the building footprint is defined just by the walls of the ground floor. Thanks a lot!