What Is A Vapor Barrier?
A vapor barrier is a thin layer of impermeable polyethylene sheeting that prevents moisture from seeping through your basement or crawl space walls (and floors). This barrier is around 10 to 20 millimeters thick and catches water and moisture seeping through your concrete, channeling it downwards to a connected drain tile system. If you have drywall or paneling on your basement walls, this will protect them from being ruined by mold, moisture, or rot. Note: In order to apply a vapor barrier to a finished basement, we will need to remove any finishes.
A vapor barrier will lower the temperature in your basement or crawl space, reduce humidity, and prevent moisture from damaging stored items, including structural supports such as joists.
When To Use A Vapor Barrier With Insulation
Insulation will prevent air from entering or escaping your basement, but it will not stop moisture diffusion. A vapor barrier will stop moisture diffusion and should be applied directly to your concrete walls (plus crawl space floors). If you decide to add insulation in your basement, it should be applied after you install a vapor barrier.
How Do We Install Vapor Barriers?


Our Basement And Crawl Space Waterproofing Services
Contact The Real Seal For Basement and Crawl Space Vapor Barrier Services In Chicagoland
What Our Customers Are Saying
George, our technician, did an outstanding job with the repair. During the process, he discovered a 2x4 that had been bolted directly into the foundation wall—a possible cause of the cracking we were seeing. He explained how that kind of pressure can lead to long-term structural issues, which we never would have realized on our own. George not only fixed the problem, but also walked me through the repair process and what was being done to ensure the wall would be properly supported going forward.
Both Rob and George were professional, knowledgeable, and respectful throughout. It’s rare to find a company where both the inspection and the repair sides are this strong. I’d highly recommend Real Seal to anyone needing foundation repair or basement waterproofing. Their team brings both skill and great communication—exactly what you want for something as important as your home’s foundation.
If you have a crawlspace want to add square footage to your home (or have a nice new spot to wait out tornados), I highly recommend reaching out to Real Seal about a conversion.
Vapor Barrier FAQs

What material can be used as a vapor barrier?
The Real Seal Basement Waterproofing and Foundation Repair uses 10 to 20-mil thick impermeable polyethylene sheeting.

Can I install a vapor barrier myself?

How long does a vapor barrier last?

What is the difference between a vapor barrier and a moisture barrier?

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

Does mold grow under a crawl space vapor barrier?

Will a vapor barrier reduce humidity?

When should I replace my vapor barrier?
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Waterproofing basements in Chicagoland and surrounding areas.
