Crawl Space Floor Joist Insulation

Instead install fiberglass batting between the joist bays which are the spaces between each set of floor joists.

Crawl space floor joist insulation.

If your space has them avoid adding insulation to the crawl space walls. Stapling fiberglass batts between joists to the underside of your home s floor presents a number of problems. While this method does work in the very short term moisture eventually builds in the crawl space and grows on this highly porous surface. If the crawl space is ventilated which is ideal because it aids in the elimination of moisture then fiberglass insulation can be easily installed under the subfloor between the floor joists.

This type of insulation allows for conditioned air to be introduced into the crawl space. It is important to secure insulation and cover it with a vapor barrier in order to prevent moisture and the mold that often follows close behind. Don t compress the insulation as it requires its loft in order to maintain its rated r value. However the insulation needs to be treated with a fire retardant.

Insulating and air sealing this perimeter zone is important because it s a major source of air infiltration and conductive heat loss. This type of crawl space also allows insulation with an r value of 19 installed in the floor joist if the crawl space and has a permanently installed dehumidifier. Floor insulation for moderate climes popular reads. Where winter temperatures are extreme opt for insulating the walls and sealing off the crawl space entirely.