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How A Crawl Space Vapor Barrier Installation Might Be Done When You Want The Space To Stay Dry

by Marc Cole

If your crawl space is always damp, you probably need to have a vapor barrier installed on the floor. Dampness is often caused when water rolls under your house when it rains, but the dampness can also be caused by water vapor that rises up through the soil beneath your house. Putting a vapor barrier down keeps water vapor from getting in the crawl space so it stays dry. Here's a quick look at the crawl space vapor barrier installation process.

Clean The Crawl Space First

A vapor barrier is tough, but it can be punctured if litter is left on the floor and someone steps on it through the barrier. The vapor barrier is placed on the floor and up the walls several inches, so everything needs to come out of the crawlspace so the installation crew can work.

The floor has to be swept as best as possible and debris removed. Also, if the crawl space has water puddles, the puddles need to be dry before the vapor barrier is put down. In addition, a drainage solution is needed so water won't keep backing up in the crawl space.

Choose The Vapor Barrier 

Your contractor may supply their favorite vapor barrier or you might get to choose your own. Vapor barriers differ in thickness. The thicker the barrier, the more expensive it is. However, you probably don't want to cut corners and get the cheapest barrier because it may not be very durable.

The contractor needs to measure your crawl space to know how much material to order. They'll also need other supplies, such as something to cut the barrier with and vapor barrier tape to close the seams. The contractor may also install insulation at the same time if it's needed, so they might bring insulation boards to the project.

Install The Vapor Barrier

A vapor barrier comes on a big roll, but it's cut into sheets so it's easy to install. The sheets may be put on the wall first and then on the ground. Seam tape is applied where two sheets join together and where the wall sheets meet the ground sheets.

This ensures your floor is sealed so no water vapor can waft up into the crawl space. A vapor barrier can also be put down when you're having work done for radon remediation. However, in that case, a vent is put in that pulls radon out from under the barrier so the radon can go outside.

When the crawl space vapor barrier installation is done, your contractor might recommend setting up a dehumidifier in your crawl space too, so the area stays as dry as possible.