Crawl Space Vapor Barrier: 8 Easy Install Steps

Crawl spaces are damp, dusty, and all around dirty, so it’s no surprise if you haven’t been down there much. But what if that wasn’t the case? What if you could create a clean, dry, usable crawl space?

Well, you can with a crawl space vapor barrier. Thanks to modern innovation, vapor barriers are some of the most effective crawl space encapsulation tools on the market. In this article, we’ll explore why a vapor barrier in crawl space is beneficial and how to install one beneath your home.

While less than 10 percent of newly built homes have a crawl space foundation, it’s important to understand what can happen without a vapor barrier.

Moisture poses a huge threat to your home. When water (or water vapor) gets below your home, it is absorbed by the wooden structural supports found in most crawl spaces. Over time, this leads to problems like mold, wood rot, or sagging floors. A wet, damp crawl space is also an ideal breeding ground for insects and rodents.   

Sealing this area with a crawl space vapor barrier is a great way to keep your home healthy. It ensures your family breathes cleaner air and wooden support beams below your home stay safe.   

A vapor barrier alone is not enough. For the most efficient protection, we recommend installing a dehumidifier, crawl space drains, a sump pump, and insulation alongside your vapor barrier to create a comprehensive encapsulation system.

One of the common crawl space red flags is mold. Mold is often the first indication of a problem. So, is it important to remove the mold before installing a vapor barrier?  

The answer depends on how long the problem has been festering and how much mold is present at the time of installation. While the United States Environmental Protection Agency says if mold covers less than 10 square feet (or a 3ft. by 3ft. area), you can clean the mold yourself, it’s best to err on the side of caution. Entering your crawl space and exposing yourself to mold and other problems can be dangerous, so it’s best to contact a mold remediation specialist for safe and effective removal.   

At Groundworks, we understand that every home is different and presents various challenges. We only recommend and install solutions tailored to meet your home’s needs.

The crawl space vapor barrier installation and encapsulation process can vary depending on each home’s condition. However, here is a general overview of how our crews complete these essential repairs:

Step 1: Diagnosis  

Before installing a vapor barrier, it’s important to do a full inspection and determine the cause of the crawl space problem. Is groundwater entering from the floor or walls? Are open vents trapping humid air inside? Is a plumbing leak dripping into the space? Ensuring the solution matches the root problem goes a long way to preventing future problems.  

Your local Groundworks inspector will consider your neighborhood’s unique soil type, the typography of your home, and the weather conditions before making repair suggestions. 

Step 2: Crawl Space Clean Up  

The crawl space then needs to be cleaned.

This step may look different for everyone depending on the condition of the crawl space. If there is water in the crawl space, it’s beneficial to dry it out with a submersible pump, fans, or a dehumidifier. Sometimes, this process may take a while. Consider mold remediation if needed.  

All fallen, wet insulation and scrap building material should be bagged and removed. 

Step 3: Crawl Space Grading & Preparation 

Next, the crawl space floor should be free of large rocks and debris, including any pests that might be inside. Collapsed insulation also needs to be removed. Finally, the soil should be raked to establish a rough grade.   

Step 4: Seal Crawl Space Vents

It’s crucial to close and conceal any open crawl space vents to avoid air, water, and pest intrusion. Your local Groundworks company will custom-fit blocks of insulation panels in the interior vent opening before fully encapsulating the crawl space. Exterior vent covers can be added upon your request.

Step 5: Install Waterproofing Measures 

Afterward, depending on the amount of water in your crawl space, consider installing a specially designed crawl space sump pump or other drainage options to remove any water that would remain beneath the vapor barrier.

Step 6: Insulate Walls 

Then, the wall insulation is attached to the interior crawl space walls with either an adhesive or a special masonry fastener.  

Step 7: Install the Vapor Barrier Liner 

Next, our team measures and cuts a high-quality, 20-mil vapor barrier to fit the crawl space, allowing several inches to run along the walls. We ensure a tight fit by overlapping seams with double-sided tape.   

Step 8: Condition the Air 

Finally, now that your crawl space has been sealed, you need to establish positive airflow. This is accomplished with an energy-efficient crawl space dehumidifier.   

While installing a crawl space vapor barrier is fairly straightforward, it can be exhausting, back-breaking work in a tight, small area. The experts at Groundworks install vapor barriers and encapsulate crawl spaces every day. As a result, we have the best products and procedures to make installation simple and effective. Our 20-mil crawl space vapor barrier locks out moisture and soil gases and is covered by a nationally backed, long-term warranty.  

Crawl space problems worsen with time, making proper encapsulation crucial. Let Groundworks work hard and eliminate your crawl space issues for good. Contact us today to schedule a free inspection!