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Thin, Leaky Walls? You Can Insulate Them With Spray Foam

by Ryan Wright

If you live in an older home with thin walls, you might assume you're just doomed to shiver winters away forever. Even if you were to cram some insulation between those walls, you wouldn't be able to get enough in there to do much good anyways, right? Not necessarily. While insulating old, thin walls with fiberglass is indeed a challenge, there is another type of insulation that actually does this duty very well: spray foam.

What is spray foam insulation?

Spray foam insulation is a newer type of insulation product. It starts off as two different liquids in two canisters. When the liquids are sprayed onto a surface using a special applicator that mixes them together, they react and expand to form a dense foam. This foam isn't like the foam in a pillow or mattress. It's hard, and its cells are closed. You can't really push down on it, and it does not absorb water.

Why does spray foam work well in thin walls?

Spray foam is a much better insulator than fiberglass or most other insulating materials. You only need a thin layer of it to block heat transfer. So even if there are only a few inches between your exterior and interior walls, you should be able to fit enough spray foam in there to keep your space a lot warmer and reduce your heat bills.

Spray foam also helps insulate by sealing up any little cracks and crevices in the walls. This can't be said for fiberglass – air blows right through it. Since spray foam is waterproof, you don't have to worry about it being exposed to a little moisture from the outdoors, either. It won't allow that moisture to transfer into your home.

Finally, spray foam can be applied through just a few small holes about the size of a quarter. It will expand to fill in the space between your walls. You don't have to worry about extensive renovations, as those small holes should be pretty easy to fill in or camouflage.

Are there any downfalls to spray foam insulation?

You do need to have spray foam professionally applied. If it's not formulated properly, it may not cure properly and will end up doing a poor job of insulating your home. So only work with a contractor who has plenty of spray foam experience.

The only other downfall is the time it takes. In most cases, after the spray foam is applied, you'll need to stay out of your home for a day or two until it cures.

For more information about wall insulation, contact a professional.