Installing a Vapor Barrier in Your Crawl Space and How It Helps Your Home

If your crawl space has leaked before, you know how much of a pain it is to clean up the standing water. The good news is that there are multiple waterproofing solutions you can employ to keep your crawl space dry.

One of these solutions involves the installation of a vapor barrier. An essential part of the encapsulation process, vapor barriers, when coupled with perimeter drainage and a sump pump, will help redirect Missouri precipitation away from your home. When do you need a vapor barrier, though, and how does it play into the encapsulation process?

Is Your Crawl Space Leaking? Signs to Look For


Before you invest in a vapor barrier, you’re going to need to look over your crawl space and determine how severe your leak is. When looking, keep an eye out for the following signs: 

  • Cooler temperatures – Your crawl space should already be cooler than the rest of your home. If you’re noticing the temperature dropping further, however, you may have a leak on your hands. Why? Because increased dampness in your crawl space makes the space more difficult to temperature control. The collected vapor will make the space cooler than it would be otherwise. If you want to track the temperature in your crawl space, be sure to leave a thermometer in the space and to monitor it at set intervals.
  • Damaged belongings – If you’re storing personal belongings or emergency supplies in your crawl space, you need to check up on them occasionally. As you do, you can check your belongings for signs of water damage or exposure to moisture. If your papers are curling up, fabric is rotting or wood is warping, then you may have a leak on your hands.
  • Pest infestations – The same cracks that let moisture into your crawl space will sometimes allow pests in, too. As such, keep an eye out for infestations of critters or insects. If they can get into your crawl space, Missouri’s precipitation definitely can.
  • Damp walls – Moisture gathering on the walls of your crawl space is a definitive sign of a leak, as it means water is not only getting into your crawl space, but it’s staying there.
  • Mold – Finally, keep an eye out for mold clusters in your crawl space. Mold thrives when exposed to dark and damp environments. If you see mold clusters, remove them and detoxify the space as quickly as possible to avoid spreading pathogens to the rest of your home. From there, you’ll need to talk to a contractor about the waterproofing solutions available to you. 

What is a Vapor Barrier?

You know what signs to look for now – but when will a vapor barrier come into play?

Vapor barriers are thick, white plastic-like sheets that drive water away from your crawl space. It is impossible for air and most gases to permeate a vapor barrier. This means moisture won’t be able to get to the belongings you’ve stored in your crawl space. Neither will loose groundwater, as the sheets will stand between the walls of your crawl space and your belongings.

Vapor barriers, as a result, are ideal waterproofing solutions in crawl spaces that see wall dampness and occasional flooding. Encapsulating your crawl space is a permanent solution that will properly seal the area from the earth.

Waterproofing Your Crawl Space With a Vapor Barrier

Vapor barriers are an essential part of the encapsulation process your crawl space can undergo if it experiences frequent or severe leaks. In general, the encapsulation process includes the following steps:

  1. Dry the crawl space out – You’ll need to do what you can to remove standing water or dampness from your crawl space before you start the encapsulation process. If you have to remove a significant amount of water from the space, talk to your contractor about installing a temporary pump.
  2. Find the leak – Once the crawl space is clean, follow the old tracks of water back to where the leak supposedly started. You should easily be able to find leaks in your walls or joints. However, if you can’t find where your leak is coming from, you may have a crack in your foundation. If you believe this is the case, talk to your contractor. You’ll need to waterproof your foundation before moving forward with your crawl space encapsulation process.
  3. Close the leak – Once the leak’s been identified, plug it up so your crawl space will stay dry during the encapsulation process.
  4. Dispose of old insulation – If your crawl space was previously insulated, you’re going to need to remove the old and water-damaged insulation. If you don’t, you risk spreading pathogens to the rest of your house or providing dormant mold particles with an environment in which they’ll thrive.
  5. Install a vapor barrier – With the old insulation removed, you can install your vapor barrier. Be sure to cut holes in the barrier to allow for pipes, electrical circuits and vents.
  6. Consider stacking other waterproofing solutions – Once your vapor barrier has been installed, talk to your contractor about the other potential waterproofing solutions you can use to keep your crawl space dry. Pairing a vapor barrier with a dehumidifier, for example, may keep your vapor barrier healthier for longer.

Don’t let Missouri’s precipitation keep you from using your crawl space. Talk to your contractor to determine whether or not a vapor barrier is the solution for you.