What is Crawl Space Insulation?

Koren Allen
Koren Allen
Crawl space insulation can help prevent frozen pipes.
Crawl space insulation can help prevent frozen pipes.

Insulating your home helps you save money on heating and cooling costs. When thinking about insulating your home, don’t forget the area under your home. Crawl space insulation is important for keeping the temperature of your home constant, as well as avoiding costly repairs resulting from frozen water pipes. The most commonly used insulation in crawlspaces is fiberglass rolls or bats, but foam board insulation is also used.

The type of crawl space insulation you choose will depend on whether your crawlspace is ventilated or not. In some areas, crawlspaces are ventilated to allow airflow and limit humidity and moisture under the home. In a ventilated crawlspace, insulation should be installed under the sub flooring of the home. The rolled strips are cut to fit between the floor joists, and held in place with either wire fasteners or chicken wire fastened to the underside of the joists. If air ducts and water pipes run between the joists, insulation can be installed directly over them, providing a thermal barrier from colder outside temperatures. Pipes and ducts that are not enclosed in this manner will need to be insulated with special insulating tape or pre-formed insulation tubes designed to protect against freezing.

Newer homes often have enclosed crawl spaces, and sometimes ventilated crawl spaces have been enclosed after construction by sealing off the vents. In this type of crawl space, insulation can be installed continuously along the masonry walls, eliminating the need to insulate ducts and pipes individually. This method also helps keep the temperature of your home constant because it incorporates the crawl space into the main thermal envelope of the home. Blanket-type crawl space insulation is installed using furring strips to hold it in place. Insulation should cover the entire interior surface of the walls and extend across the floor of the crawl space two feet (.6 m) from the wall, to provide the most effective heat and moisture barrier.

There are some special problems associated with crawl space insulation. Because it is installed close to or below ground level, crawl space insulation is particularly vulnerable to damage caused by rodents, termites, and water. Prevention is the best cure for this problem, so it is important to inspect your crawl space regularly for signs of damage. Be sure and check building regulations and codes for your area. Some localities require a termite shield to be installed with crawl space insulation. Your locality may also require a visible gap near the foundation to facilitate termite inspections. Make sure you are in compliance with local requirements before completing your installation.

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    • Crawl space insulation can help prevent frozen pipes.
      By: Renate Micallef
      Crawl space insulation can help prevent frozen pipes.