I’m a builder and remodeler along the coast of Delaware. When we’re not building right on the beach, where we use piling foundations, local practice is to build shallow crawlspace foundations. The bottom of the footing is typically 24 inches below grade, and the foundation walls might be three to five blocks tall. The dirt inside the walls is typically roughly leveled and covered with loose-laid 6-mil poly. The walls have vents, but there is usually no perimeter drain.
Because the excavated dirt floor is below the surrounding grade, and we’re in an area where the water table is relatively high, wet crawlspaces are the rule.
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