SLAB ON GROUND A substructure that is constructed on-site and built flush on a concrete slab.
BASEMENT A basement is an excavated area below the ground floor, typically at least 8 feet in depth, which includes the walls, a slab floor, and a stairway from the ground floor. The total percentage of the first floor of the residence that has basement below.
OPEN FOUNDATION A raised substructure not structurally attached to the foundation; sometimes enclosed with lattice.
CRAWL SPACE An excavated or unexcavated foundation area below a residence, less than 5 feet in depth, that is generally used for access to plumbing and heating equipment.
POSTS & PIERS A substructure generally rectangular in cross section, supporting the base of the dwelling.