Crawl spaces, small or under the entire house, are a considerable cause of air leakage and moisture infiltration. They are a constant heat sink especially in the winter when the floors of the rooms above crawl spaces remain cold making it difficult and expensive to bring them to a comfortable temperature. Batt insulation that is typically installed in crawlspaces quickly molds and mildews rendering it an ineffective health hazard.
Closed-Cell Spray Foam with its built in vapor barrier is the only answer to properly sealing a crawl space. It is the answer for both concrete and dirt crawl spaces. Because Spray Foam expands to seal all cracks and crevices, it also acts as a critter deterrent.