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Can You DIY Crawl Space Encapsulation?

December 6th, 2023 | 6 min read

By Kilian Agha

You've noticed some issues in your crawl space. Maybe it’s moisture buildup, mold, or even critters making themselves at home. You know something has to be done, and you're wondering if crawl space encapsulation is something you can tackle on your own.

At South Central Services, we've installed spray foam insulation in hundreds of homes. For many of those homes, we have also encapsulated the crawl space. We speak to many homeowners about encapsulation because crawl space issues are prevalent in our service area. Many houses in Biglerville, Gettysburg, and East Berlin have vented crawl spaces.

The truth is that DIY crawl space encapsulation is possible. However, the most critical thing about encapsulation is ensuring it is done correctly.

By the end of this article, you will understand:

  • The complexities involved in DIY crawl space encapsulation
  • The benefits and risks of encapsulating your crawl space yourself
  • How professional services compare to DIY attempts

What Is Crawl Space Encapsulation?

Crawl space encapsulation involves sealing the crawl space’s floor and walls with a vapor barrier. The goal is to prevent moisture, mold, and air quality issues. The vapor barrier on the floor is usually made of a thick plastic sheathing. Two to three inches of closed cell spray foam are installed on the walls, providing a thermal barrier as well as a vapor barrier. The encapsulation process may also include installing a dehumidifier to regulate humidity levels.

Encapsulating your crawl space can improve air quality, increase energy efficiency, and prevent structural damage over time. An encapsulated crawl space can create a more comfortable living environment by regulating temperature and humidity. If your family would want to leave your current home someday, encapsulation can also increase your resale value.

An encapsulated crawl space with wrapped pillars and HVAC vents. The spray foam in the rim joists is visible.

In southern Pennsylvania, not many crawl spaces we see are encapsulated. If any measures have been taken to improve the crawl space, it is usually a thin plastic sheet on the floor. This type of solution will not improve air quality or help with energy efficiency.

Can You Encapsulate Your Crawl Space Yourself?

Crawl space encapsulation can be completed as a DIY project. However, a beginner can find DIY encapsulation difficult to pull off successfully. Let's examine three things you'll need to improve your chances for an effective DIY crawl space encapsulation.

1. Home Improvement Project Experience

Crawl space encapsulation is a complex task. You’ll need a thorough understanding of your home's foundation, moisture levels, and potential mold issues. Other aspects of your home may also be involved, such as your HVAC system and its vents. You'll also need to be comfortable working in confined spaces. It’s known as a crawl space for a reason.

You may find this task challenging if you're not experienced in home improvement projects. Even if you do thorough research and feel comfortable with the steps involved, the accessibility of the crawl space can still pose challenges. Tasks that seem simple to complete can be significantly more frustrating if you’re physically confined or uncomfortable.

2. Correct Tools And Materials

To prep your crawl space for encapsulation, you'll need specific tools. Depending on the state of your crawl space floor, these tools could include a short-handled shovel, a box cutter, or a measuring tape. Any existing insulation in the ceiling of your crawl space will also need to be removed, which means having the right personal protective equipment (PPE) and bags to dispose of the old insulation.

Once the area has been prepared for encapsulation, you will need to acquire the encapsulation materials. The vapor barrier material for the floor should be at least 12 mil thick for durability and effectiveness. You'll also need foam board to attach to your walls and seam tape to seal off your vapor barrier. Depending on the moisture content of your crawl space, you may need a dehumidifier.

3. Time To Invest

Crawl space encapsulation generally takes experts between one to three days. A beginner may need anywhere from four days to a week to complete an effective encapsulation job. Additionally, the length of the project depends on the size of your crawl space. If your crawl space has the same footprint as the first floor of your home, it will take significantly longer to cover that square footage.

Your encapsulation project may experience other delays from unexpected issues like structural damage. If you recognize structural problems during your preparations, you should call a professional.

How Much Does A DIY Crawl Space Cost?

DIY crawl space encapsulation kits are available online. The price tag, as well as what is included in a DIY encapsulation kit, will depend on the retailer.

One of the DIY kits we found online, which is for a 1,500 square foot crawl space, cost approximately $3,000. The kit includes vapor barriers, tapes, and a dehumidifier. However, it does not offer any insulating material for the crawl space walls.

In our climate zone, insulating the walls of the crawl space helps eliminate cold infiltration. If you purchased a kit like this, you may have to purchase foam board separately for wall insulation.

While this kit also includes a dehumidifier, not every retailer may include dehumidification in their kits. Dehumidifiers could cost an additional $2,000 to purchase separately.

Every crawl space is a different size. While many crawl spaces are within 1,100 and 1,400 square feet, that range does not account for the dimensions of every crawl space. It is difficult to estimate a cost per square footage for crawl space encapsulation, but you should expect to spend at least $3,000 on basic materials.

Risks Of DIY Crawl Space Encapsulation

For many homeowners, the unpleasant issues related to crawl spaces are not worth dealing with on their own. While they may end up spending more money by hiring a contractor, they avoid various risks related to doing encapsulation themselves. If you choose the DIY route for your crawl space, you will take on some risk. Let's examine three possible risks related to DIY crawl space encapsulation.

1. Lack Of Insurance

One significant drawback of DIY work is the lack of insurance. Crawl space encapsulation is no different. If something goes wrong with your DIY encapsulation job, the cost to fix it comes out of your own pocket. Whether you hire a professional or purchase more materials to redo the work yourself, there is no warranty to fall back on to cover the costs.

Professional services often come with warranties that cover both materials and labor. For example, homeowners who work with our team at South Central Services are insured. Any problems that could arise due to installer error would be handled at no cost to the customer.

2. Safety Concerns

Crawl spaces can be hazardous environments housing spiders, cockroaches, and mice. The low ceilings can make the encapsulation work physically demanding. Depending on your mobility, working in your crawl space could be dangerous due to these accessibility issues. Proper safety gear, including gloves, masks, and knee pads, is essential for this project.

A crew member of South Central Services installing dimple mat in a crawl space. Located in Chambersburg, PA.

3. Poor Quality Of Work

Unless you have experience in this area, your DIY project's quality will likely not match that of a professional service. An improperly encapsulated crawl space offers no benefit to you or your home, but still costs your time, money, and energy. Additionally, any issues your crawl space causes will still need to be appropriately dealt with.

Even with home improvement experience, your crawl space can present unique challenges. Something as simple as the local weather and humidity levels can significantly impact the effectiveness of your crawl space encapsulation project. High humidity levels can make it challenging to maintain a dry crawl space.

You may need to rent a fan to circulate air and dry out the area before attempting encapsulation. No matter how well prepared you are for your project, the space has to be ready for the work as well.

Professional Encapsulation vs. DIY Encapsulation

If you're considering a DIY route, paying a professional is likely the last thing you want to do. However, if any of the risks or potential issues we have discussed have given you cause for concern, you may want to hire a professional. Let's examine the two primary benefits of working with professionals.

Expertise And Inspection

Professional services come with years of experience and the ability to inspect for structural issues and mold remediation. They also usually offer warranties on their work, providing you with peace of mind.

Professionals also have access to high-quality materials that may not be readily available to the average homeowner. For example, a professional encapsulation job uses closed cell spray foam for the walls. Many DIY encapsulation kits use foam board instead. Spray foam will offer superior performance compared to foam board.

A crew member at South Central Services installing closed cell spray foam on the walls of a crawl space in Chambersburg, PA.

Cost And Time

While hiring a professional service might seem more expensive upfront, professionals can complete your project more quickly and efficiently. The job will be done right on the first try, so you will save on any potential future costs of fixing a poorly done DIY job.

We recommend getting a few professional quotes to compare against the cost of DIY encapsulation. Professional contractors can also provide valuable insights into local building codes and regulations you may not be aware of.

The Bottom Line About DIY Crawl Space Encapsulation

Crawl space encapsulation is a complex project requiring significant time commitment and specialized knowledge. While it's possible to DIY, the risks and challenges often outweigh the benefits. Encapsulation needs to be done correctly to offer any benefit to you.

If you're not confident tackling this project, we recommend working with a professional. Professional encapsulation will deliver the result you need and may be more cost-effective in the long run.

Now that you know whether DIY encapsulation is feasible for you, your next step is to:

Kilian Agha

Kilian has co-owned and operated South Central Services for 8 years. He is passionate about community involvement. In his spare time, he enjoys being with his family, playing ice hockey, and going fishing with friends.