For SDE Tool purposes, a basement is a below-grade enclosure. All sides of the foundation are enclosed with at least one side below grade. The basement can be finished or unfinished. This is distinct from a crawlspace or continuous wall with a slab because these foundation types are not below grade.

This definition of a basement is much broader than that used by the NFIP in which a basement refers to any area whose floor is below grade on all sides.