Fiberglass is sold in batts that fit between wall studs and ceiling joists. Larger fiberglass blankets can be set on top of joists in an attic, while loose fiberglass can be blown into cavities. You can buy fiberglass that is wrapped or made with “low-itch” fibers, thus eliminating a major irritant for many people. Fiberglass is readily available, inexpensive and easy to install. It is the best choice for do-it-yourselfers when insulating unfinished walls.
Cellulose is a loose-fill insulation that is growing in popularity. Made primarily from recycled newspapers and treated with a fire retardant, cellulose is usually blown into wall and ceiling cavities with a special blowing machine. Blowers can be rented at many tool rental stores, and home centers will sometimes loan you a free one if you buy your cellulose from them. Though trickier to install that fiberglass batts, cellulose is a good choice for filling finished walls. Just cut a hole large enough for the hose, then patch the hole when you’re finished blowing in the cellulose.
Rigid panels of foam or polystyrene are particularly useful on concrete floors in garages and basements and on basement walls. They offer a high insulation value without a lot of thickness.
- How To Insulate Garage Floors with Sleepers & Rigid Foam
- How To Insulate Garage Floors with Plywood & Rigid Foam
Spray foam is used in the walls and ceilings of new homes, but as a DIY product it is most often used for filling small cracks and gaps around windows, doors, vents and other objects.