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Can Vapor Barrier Control Humidity? – Myth #10

image of crawl space vapor barrier

This week we're on myth #10 of our Crawl Space Myths Series! A lot of contractors will tell you that installing a vapor barrier is enough to control humidity in your crawl space. We think that's a myth, let us explain why. You can check out the entire 13 Video Myth Series Here.

Controlling Crawl Space Humidity with Plastic

Okay, so we get asked all the time, "Does installing the vapor barrier control humidity?"

Yes, it does... but it doesn't control humidity enough to where you still don't need a dehumidifier. You should also install a crawl space dehumidifier to properly control humidity.

Just like standing water alone doesn't control humidity, a vapor barrier alone will not control humidity. You've got to address the standing water, install the vapor barrier, and still put in that dehumidifier that you don't want to put in. A dehumidifier is the only way to continuously control humidity in your crawl space.

Crawl Space Vapor Barrier

Now keep in mind, the vapor barrier does not prevent all ground moisture from getting into the crawl space. It's actually a retarder, so a vapor retarder keeps the humidity behind the vapor barrier, but that humidity can eventually escape through the seams and where it's attached to the foundation wall.

So if somebody comes in and tells you, "I'm gonna put a vapor barrier down in your crawl space, Mr. Jones, and your humidity's gonna be under 60%." That's not true. That's a myth.

We hope that you've found this series helpful. Stay tuned as we continue next week!

Need Help Installing a Vapor Barrier

Do you need help with crawl space encapsulation, fixing your crawl space humidity problems or installing a vapor barrier? If so, we can help. Please contact us to schedule your assessment. Also, let us know in the comments below if you'd like to suggest a future blog post.

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