Question 1

Does basement insulation need a vapor barrier?

Accepted Answer

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Yes, basement insulation needs a vapor barrier due to its susceptibility to moisture seeping in from the outside of the house. You should install a moisture barrier before you install insulation or purchase insulation that comes prebuilt with a moisture barrier to avoid water damage in your insulation and costly mold and water remediation expenses.

Question 2

How do I add insulation to existing walls?

Accepted Answer

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If you need to insulate behind finished walls, the best option will likely be to have an insulation professional install blown-in insulation. The installation requires small holes cut in your wall, after which the installer can blow loose-fill insulation into the void. After the installation, you’ll have minor drywall patching, which shouldn’t cost more than $100. Compared to ripping down the existing drywall, using a different type of insulation, and replacing and finishing the drywall, this should save you hundreds or even thousands, depending on the size of the room you’re insulating.

Question 3

How do I know if my crawl space needs insulation?

Accepted Answer

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Three signs that you need crawl space insulation are drafts, high energy bills, and mold. Drafts can start in crawl spaces and cause hot or cold air to spread to the rest of your home through holes in the floors and walls. And even if your entire home is well-insulated, you can still feel an unchecked draft from your crawl space and in your utility bill. Uninsulated crawl spaces can let in air and moisture, and because they’re built directly on the ground and difficult to dry out, they are hotspots for mold and mildew.

Question 4

What happens if you don't install a vapor barrier?

Accepted Answer

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While not every wall requires a vapor barrier, if you do need one and don’t install it, moisture can get between the walls of your home. This can lead to water damage from mold growth or rot, and the excess moisture could also attract pests, including termites, cockroaches, or ants.

Question 5

Does a monolithic slab need insulation?

Accepted Answer

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Monolithic slabs don’t require insulation, but many homeowners choose to have their contractors install insulation under the slab during construction. This can help improve home efficiency even more and keep indoor temperatures more stable. Slab foundations are more energy-efficient than uninsulated crawl spaces and basements, and insulated slab foundations are more energy-efficient than insulated crawl spaces and basements.