Foam Board Insulation Floor Joists

This method can be hundreds of dollar less than the cost of using the commercially applied spray foam.

Foam board insulation floor joists. Foam board insulation is used on attics and walls yet it can also be used to insulate your floors. The best insulation material for crawl spaces is rigid foam insulation board. Instead of installing the foam insulation between floor joists in the crawl space the foam board is installed against the crawl space foundation walls. Rigid foam is the best insulation for rim joists.

Low pressure foam how to seal rim joists. You can insulate second floor rim joists following the same steps shown here if you happen to tear out a ceiling during remodeling. If you need to insulate these rim joists it s best to hire a cellulose insulation contractor. Seal and insulate using rigid foam board insulation.

A do it yourself friendly method for sealing and insulating the rim joist or band joist area is to use rigid foam up against the rim joist. Also insulate 4a any portion of the floor in a room that is cantilevered beyond the exterior wall below. Unsealed rim joists rob homeowners of money energy efficiency and comfort. Most people do not think about insulating their floors unless perhaps it s their attic floor.

4c as an alternative to floor insulation foundation walls of unvented crawl spaces. 4b slab floors built directly on the ground. But insulating your floors is a good idea for many reasons including energy efficiency and height adjustments. To prevent these problems only air impermeable insulation either rigid foam or spray polyurethane foam should be used to insulate the interior of a rim joist.

Unlike fiberglass rigid foam insulation does not absorb water support mold or allow air to pass through. We chose 2 in thick r 10 extruded polystyrene don t use expanded polystyrene which is a less effective air and moisture barrier. Two story homes usually have another ring of rim joists above the first floor ceiling.