Question 1

Should you remove old insulation before adding new insulation?

Accepted Answer

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You do not always need to remove old insulation before adding new. If the existing insulation is in good condition—not wet, physically damaged, moldy, or infested with pests—you can add new insulation directly on top of it for a compounding effect. You can also mix different types, such as adding blown-in insulation around existing fiberglass batts.

However, removal is recommended if the old insulation is compromised by water damage or pests. You should also remove it if you plan to install a different type of insulation, like switching from roll or batt insulation to spray foam. If the existing insulation is very old or damaged, you will likely get more benefit from removing it and starting fresh.

Question 2

Is installing crawl space insulation worth it?

Accepted Answer

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Yes, crawl space insulation is worth it if installed correctly. Installing insulation in your crawl space will improve the air quality, help stabilize your home's temperature, lower your energy bills, and prevent pests from entering your home. Though you’ll pay more to install insulation initially, the savings you get from installing insulation can help offset those initial costs over time.

Question 3

What are the disadvantages of wool insulation?

Accepted Answer

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Each of the three types of wool insulation has particular disadvantages. While their R-value is higher, they all cost more than fiberglass versions. Installing mineral wool and sheep wool requires protective gear. Because of its vulnerability to insects, chemicals are used in its production. Hemp wool is more costly to install than other types because additional tools and labor are involved.

Question 4

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 5

What is the lifespan of crawl space insulation?

Accepted Answer

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The lifespan of crawl space insulation depends on how well you maintain your insulation and the type of insulation. Fiberglass will need replacing every 15 to 20 years on average if you don't have a vapor barrier in place. If you do have vapor barriers in place, then your insulation could last much longer. Spray foam insulation can last anywhere from 80 to 100 years.