How To Insulate A Crawl Space With A Dirt Floor

Applying spray foam to the dirt floor of your crawlspace may be one of the easiest and most effective solutions and if so then you would be best not to insulate the joists over your head and just heat that space instead.

How to insulate a crawl space with a dirt floor. Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space. Cut rigid foam pieces to size with the saw and attach the pieces to the inside crawl space walls with the latex adhesive. Applying spray foam to the dirt floor of your crawlspace may be one of the easiest and most effective solutions and if so then you would be best not to insulate the joists over your head and just heat that space instead. The sill plate is the first piece of framing lumber and it runs on top of the crawl space wall.

This will give you the thermal barrier between the crawl space and your living space as well as help keep the air from getting from the crawl space into the living space. You could also use batt insulation but don t. Aim for as few seams as possible by installing large sheets of foam. To insulate the crawl space i would use a closed cell two pound 907 gram spray foam because it will act as both your vapour barrier and insulation.

If you would like to keep your crawl space vented because you live in a low humidity environment we recommend insulating the crawl space floor with fiberglass or rock wool mixed with spray foam for air sealing. Seal seams between the boards with the pvc tape. Cover the walls with insulation from the sill plate to the plastic covered dirt floor. In this video home renovation brothers dave and rich demonstrate how to insulate a crawl space.

Unless there are excessive moisture problems in the crawl space use unfaced fiberglass batts to insulate the walls. Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates. Insulate the crawl space walls.