How To Insulate Floor Joists In Crawl Space

Insulating the space between the joists in a basement or crawlspace can help reduce your energy bills.

How to insulate floor joists in 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. This type of insulation allows for conditioned air to be introduced into the crawl space. The sill plate is the first piece of framing lumber and it runs on top of the crawl space wall. Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space.

Cut the insulation to length using a square and sharp utility knife. Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances. 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. In those days common building practice was to insulate the floor above the crawl space and to leave the crawl space s wall vents open so any moisture buildup would vent to the outside a.

Here s how to insulate under a floor. Stapling fiberglass batts between joists to the underside of your home s floor presents a number of problems. When the basement or crawl space has vents installed insulating joist bays. Cover the walls with insulation from the sill plate to the plastic covered dirt floor.

While this method does work in the very short term moisture eventually builds in the crawl space and grows on this highly porous surface. Crawl space insulation basics. However the insulation needs to be treated with a fire retardant. Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates.

Where winter temperatures are extreme opt for insulating the walls and sealing off the crawl space entirely.