Video answer · Seal Tech Insulation
How Do You Stop Moisture and Pests in a Crawl Space?
Seal it. Sealing stops crawl space moisture and makes it harder for pests to get in.
The short answer
Seal it. Closed-cell spray foam on the crawl space walls and rim joists, plus a heavy vapor barrier over the ground, turns a damp, open crawl space into a dry, sealed one that pests have a hard time getting into.
Why crawl space moisture causes 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
- Remove damaged or contaminated insulation and debris.
- Seal the rim joists and foundation walls with closed-cell spray foam.
- Lay a heavy-duty vapor barrier over the ground and seal it to the walls.
- 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.
Further reading: Where to Insulate in a Home (U.S. Department of Energy).
Fix your crawl space for good
We will inspect it and show you what is going on down there.