How Do You Stop Moisture and Pests in a Crawl Space?

Why crawl spaces cause problems

A vented crawl space with a dirt floor pulls in humid outside air and moisture from the ground. That moisture can lead to musty smells, mold, wood rot, and cold floors above. Damp, sheltered spaces with gaps are also exactly what mice and insects look for.

The fix: encapsulation

1. Remove damaged or contaminated insulation and debris.
2. Seal the rim joists and foundation walls with closed-cell spray foam.
3. Lay a heavy-duty vapor barrier over the ground and seal it to the walls.
4. Seal vents and openings so outside air and pests cannot get in.

Once the crawl space is sealed, it stays drier and the floors above stay warmer. Some homes also need a dehumidifier or conditioned air to manage humidity. Your evaluation will tell you.

Why spray foam helps with pests

Cured spray foam is not a food source and does not give rodents soft nesting material the way fiberglass does. Sealing gaps also removes many of their entry points.