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10 Crawl Space Insulation Tips and Ideas

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A crawlspace is similar to a basement, but it is too low to be functional. Usually, there are different types of crawlspaces, with dirt floors or other types, vented and unvented, and many more specific characteristics. The next sections walk you through the most important 10 tips and ideas if you want to insulate your crawlspace.

1. Unclutter the Space

First of all, unclutter the area so you can move around. You may install a sump pump to avoid water accumulation in your crawlspace.

2. Check Humidity Levels

You should not vent crawlspaces as it brings in moisture. It is best to use a dehumidifier in order to keep low humidity levels and avoid condensation on surfaces that lead to mold growth and other issues.

3. Start from the Bottom Up

The best way of insulating your space is to start from the bottom up. You should start insulating the walls first, not the ceiling.

4. Use a Spray Foam

One of the easiest ways to insulate a crawlspace is to use eco-friendly spray foam, but this might require professional help. It also acts as a vapor barrier.


5. Insulate the Walls

It is mandatory to have fire protection in some states if the crawl space is more than 5 feet high and uses foam products. Another option is to use EPS foam boards on the concrete walls using an appropriate adhesive. Rock wool does not require fire protection because it does not burn, but it needs to be applied on a poly membrane placed on the concrete to act as an air barrier.

6. Seal the Vents

If you have any vents openings, make sure you seal them. You can install vent covers or caulk plywood.

7. Rim Joists

You must seal all sills and rim joists. You can use caulk or a high-quality foam sealant for the joints between the sill and the wall.

8. Vapor and Air Barriers

There are numerous air and vapor barriers available on the market in different thicknesses. One option is to use 6-mil polyethylene plastic vapor covering to keep the ground dry.


9. The Subfloor

If your crawlspace has any holes for plumbing or electrical wiring, you also need to seal them. You can use foam spray to cover all the crevices.

10. Maintenance

After you insulate your crawlspace, you need to conduct regular maintenance in order to ensure that the insulation is still in good condition. For instance, you may need to replace some parts of it in case any damage occurs over time because of insects or rodents.

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