Crawl Space Insulation & Vapor Barriers in Jasper, AL

Crawl space insulation and vapor barriers deal with the most common problem in Walker County homes: the space under the floor. Most houses here sit on crawl spaces with vents to the outside. In summer, humid air flows in and condenses on ducts and floor framing. In winter, cold air flows in and chills the floor. Bare dirt adds moisture year-round.

Start with a liner

A heavy plastic vapor barrier over the dirt cuts the moisture rising from the ground. Seams are overlapped and taped, and the edges are run up the walls a bit. On its own, a good liner often makes a crawl space noticeably drier.

Then decide: floor or walls

If the crawl space stays vented, the floor above is insulated. Alabama's code summary lists R-19 for floors in zone 3, and the Department of Energy suggests R-19 for an uninsulated floor. Batts often sag and fall in damp crawl spaces, so we either support them well or use closed-cell foam under the subfloor.

If the crawl space can be closed off, the vents are sealed, the liner runs up the walls, and the walls are insulated instead; the code summary lists R-13 or R-5 continuous for crawl space walls. The space then needs humidity control, usually a dehumidifier.

Water and hillsides

Walker County lots are often on hillsides, and water runs toward foundations. If water stands in the crawl space after rain, gutters, grading or a drain need to come first. A liner over a puddle hides the problem without fixing it.

Ducts under the house

Ducts that run through a vented crawl space sweat in summer and lose heat in winter. Sealing the crawl space brings them into milder air; if it stays vented, we point out ducts that need sealing or better insulation by your HVAC company.

Rim joists and termites

Sealing the rim joist with closed-cell foam is part of almost every crawl space job. On foundation walls, we leave an inspection strip so a pest control company can check for termite tubes. Get a free estimate