If you've decided to put new insulation in your crawl space, talk to an insulation company about the best type of insulation to use. They may recommend spray foam insulation or foam boards. Insulation is put on the walls and ceiling of your crawl space.
If your crawl space has a dirt floor, you may also want to install a vapor barrier on the floor to keep moisture from wafting up and keeping the area damp. Here's how foam boards and spray foam insulation compare.
Foam Boards Are Less Expensive
Foam boards themselves are less expensive than spray foam, but they are more complicated to install, so installation takes longer. However, the boards are easy to work with and they can be trimmed with a utility knife, pressed against the wall and ceiling, and attached with adhesive or screws.
Spray foam insulation is one of the more expensive types of insulation. It comes as a liquid in a tank. There are actually two liquids that mix together as they are sprayed out. When they mix, they create foam that expands in size to fill gaps and cracks in the walls and ceiling.
Spray foam can be sprayed directly on concrete crawl space walls or a wood ceiling. It's tricky to control the foam unless you're experienced since the foam rapidly expands. The contractor has to wear protective gear when working with spray foam due to the toxic fumes created as the liquid is sprayed.
Both Types Of Insulation Are Closed Cell
Foam board insulation is constructed with closed cells. That means they can act as a water and vapor barrier in your crawl space. Spray foam insulation comes in open cell and closed cell foam. Your contractor is likely to choose closed cell foam for a crawl space so the foam can guard against water and water vapor.
Foam Boards Need Help Sealing Leaks
One advantage spray foam has over foam boards is that the foam fills in air leaks by itself as the foam expands. This makes it a good choice for a crawl space that has a lot of drafty air leaks. It also makes installation much quicker and easier.
Foam boards can't expand and fill irregular spaces, so all of the air leaks in your crawl space have to be sealed by hand with a can of spray foam, and that could take a long time and some spots might even be missed.
Both types of insulation have similar insulating qualities, so you may need help choosing the best insulation for your crawl space. Talk to the insulation company and get advice before you make your decision.