Insulate Floor Over Unheated Space

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.

Insulate floor over unheated space. Fiberglass insulation on the floor joists in a crawl space will help keep the floor above warm. To insulate the floor mr. Layer of cellofoam foil faced rigid insulation over the bottoms of the joists then covered the insulation with 1 2 in.

If your crawl space isn t ventilated insulate the walls of the crawl space rather than the subfloor of the room above. This requires less insulation and will eliminate the need to insulate ducts and pipes separately. Mike put two layers of r 13 unfaced fiberglass batts in the joist cavities ran a 3 4 in.

However in a moist ventilated crawl space this insulation will eventually rot and become soaked with moisture. If all the work is done carefully you can effectively insulate a floor over a cold space using fiberglass batts. 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.

It will also help to stop that echo that can be heard when you walk on the floors suspended over a crawl space. 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. Install an air and vapor barrier over the floor and tape it to the insulation.

You may also want to install a polyurethane vapor barrier over the dirt floor for further protection. Use caulk or foam sealant to seal the joint between the top of the crawl space wall and the sill. Install blocking either wood or rigid foam under the kneewalls and insulate the walls floor and ceiling as shown.

This will cause it to fall off the ceiling and on to the floor. Oriented strand board osb to keep out pests. The subflooring is 3 4 in.