How to Insulate a Heated Crawl Space
Heated crawlspaces can be insulated with fiberglass batt insulation that does not have a paper face. Since heated crawl spaces are unvented they are considered to be one of the key insulation priorities for a home, according to the U.S. Department of Energy (see References). Insulating heated crawl spaces with fiberglass batts helps to hold heat in the crawlspace making the floor above warmer. It also helps to prevent pipes from freezing. Using fiberglass batts in this instance eliminates fire dangers posed by some types of rigid foam insulation when used where it is not going to be covered with an approved fire-resistant material. Does this Spark an idea?
Things You'll Need
- Unfaced fiberglass batt insulation
- 3-inch square head cap nails
- 6-mil black plastic
- Tape
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Instructions
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Lay down plastic over the ground of the crawl space. Lap seams by at least 6 inches and tape the seams as well.
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Wrap plastic up the sidewalls by at least 6 inches and tape in place.
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Cut fiberglass batts to fit between joists and against the interior side of the rim board and nail to the rim board. If the rim board is inaccessible, nail the fiberglass batts to the edge of the sill plate.
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Drape the fiberglass batt down over the sidewall and cut it 2 feet longer than necessary. Allow the excess to cover the plastic sheet from the wall toward the center of the crawl space.
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Bring edges of each batt tightly against the previous one. Cut batts to fit around joists as work progresses.
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Tips & Warnings
Wear a properly fitting dust mask of the appropriate type when working with fiberglass. Button long sleeves and wear long pants. Wear a head covering. Buy fiberglass batts with the highest R-value you can afford. Do not allow the fiberglass to get wet.
A crawl space that has standing water, intermittent water flow or heavy moisture accumulation will need the moisture issue permanently taken care of before any insulation is installed.
Do not use this procedure on a vented crawl space.
Follow local building and fire codes.
