With proper crawl space insulation, uncomfortable indoor temperatures during summer and winter, excessive moisture accumulation, frozen water pipes, and high energy bills can be problems of the past for many homeowners. By proper crawl space insulation here, we mean installing the right type and amount of insulation, providing sufficient drainage, controlling moisture and sealing all air leaks.

Sealing all air leaks in your homes crawl space can significantly decrease your winter heating bills and enhance your interior comfort. As heated air rises inside your home, cold air is drawn into poorly-sealed crawl spaces via leaks (small and large). To stop cold air from infiltrating into your crawl, you need to seal and insulate it properly. Heres a detailed guide on how to insulate the crawl space.

Seal Gaps

The primary step in stopping the infiltration of air into the crawl space is to seal gaps and cracks along wooden rim joists sitting over the walls of the crawl space to support your house. You also need to seal any gaps around wires and pipes passing through the foundation walls of the crawl to the outside. Note that caulk can only seal gaps and cracks of up to a quarter-inch wide, so if your home has bigger and wider cracks, consider using expanded spray foam.

Insulate Crawl Space Rim

Using rigid foam insulation boards or insulation batts, insulate around the rim of your crawl to help stop the loss of heat via cold air conduction. Install your preferred insulation in the cavity over the foundation walls where the rim joists connect with the floor beans. Then, cut the appropriate size of the insulation and put it against the rim joist. Hold the insulation in place using a duct tape.

Plug Holes

You also need to stop air from the crawl space from infiltrating into your living space. You can do this by sealing around vents, wires and pipes that penetrate the crawl space ceiling via holes, into your living space. Of course youll need an expanding foam sealant or caulk to do this choose one. Stop cold air infiltration by applying weatherstripping to trap doors or hatchways that provide entry to crawl spaces.

Cover The Walls

Cover the inside of the exterior walls using a rigid foam insulation board secured to the walls by a construction adhesive. Then, use exterior plywood or commercial vent covers to seal the foundations air vents from outside and caulk. Unroll plastic vapor barrier (preferably a heavy sheet) over the floor to prevent moisture build-up in your dirt floored crawl space. Finally, tape the sheets to each other, as well as to the insulation on the walls.

Make your indoor living space more comfortable by using these steps to stop cold air from infiltrating into your crawl space.