Insulate Floor Over Unheated Space

Layer of cellofoam foil faced rigid insulation over the bottoms of the joists then covered the insulation with 1 2 in.

Insulate floor over unheated space. However in a moist ventilated crawl space this insulation will eventually rot and become soaked with moisture. It will also help to stop that echo that can be heard when you walk on the floors suspended over a crawl space. This requires less insulation and will eliminate the need to insulate ducts and pipes separately. Insulating floors above unheated garages when insulating floors above unconditioned garages first seal all possible sources of air leakage.

This will cause it to fall off the ceiling and on to the floor. Install blocking either wood or rigid foam under the kneewalls and insulate the walls floor and ceiling as shown. Fiberglass insulation on the floor joists in a crawl space will help keep the floor above warm. Install an air and vapor barrier over the floor and tape it to the insulation.

Smaller room over a large garage it is important to maintain a continuous thermal boundary between conditioned and unconditioned spaces. Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates. The weak link in this situation is the kneewalls. Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space.

To insulate the floor mr. The mistake a lot of contractors make when insulating is they fail to insulate the floors over an unheated area such as a garage or the insulation is not properly installed. The subflooring is 3 4 in. This strategy has the added benefit of minimizing the danger of contaminants from car exhaust paint solvents gardening supplies etc in the garage migrating into the conditioned space.

If your crawl space isn t ventilated insulate the walls of the crawl space rather than the subfloor of the room above. But the more plumbing wiring central vacuum pipes and the like that run through the floor the harder it is to achieve a careful fit and the more i m inclined to use a blown in or sprayed in product. If all the work is done carefully you can effectively insulate a floor over a cold space using fiberglass batts. Do it yourself video on how to insulate the exposed floor over an unheated area using roxul comfortbatt r28 canada or r30 usa and roxul comfortboard is i.

Use caulk or foam sealant to seal the joint between the top of the crawl space wall and the sill.