Insulating a Crawl Space

Why install insulation in a crawl space? A crawl space is an unfinished, accessible area below the ground floor of a building. Proper insulation can help protect your living space from outside temperature changes and cold or hot air moving in through the bottom of a house.

There are two types of crawl spaces: vented and unvented. Vented crawl spaces open to the outside, while an unvented crawl spaces is part of the basement – finished or unfinished.

In a vented crawl space, the underfloor should be insulated — similar to how it is in ceilings. This may be done before or after the subfloor has been installed. JM ComfortTherm®, Kraft-faced and unfaced insulation are all possible products to use for this application. With Kraft-faced insulation, the facing is generally against the subfloor.

In an unvented crawl space, you should insulate the perimeter walls.