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How To Fix A Wet Crawl Space

August 7th, 2024 | 4 min read

By Alexis Dingeldein

Your crawl space has issues. The odor is overwhelming, and the environment could be compared to a swamp. It is wet, disgusting, and possibly downright scary. You’re tired of ignoring the problem. What will it take to fix your crawl space?

South Central Services has insulated hundreds of homes with spray foam. In our service area, crawl spaces are often the stuff of nightmares. We take pride in walking (or rather, crawling) through to provide a thorough and final solution. Your wet crawl space can be fixed, which will make your home safer and more affordable to live in.

By the end of this article, you will understand:

  • Differences between damp and wet crawl spaces
  • What steps to take to fix a wet crawl space

All Vented Crawl Spaces Have Unmanaged Moisture.

In Franklin County and the surrounding counties in PA, most crawl spaces are vented. Vented crawl spaces aren’t supposed to have moisture issues, but they all do. A vented crawl space cannot generate enough airflow to actually dry out the space.

Batt insulation falling out of the ceiling of a crawl space in Franklin County, PA.

Since crawl spaces are below the ground, the area is already damp. Vents in a crawl space let more moisture and uncontrolled air inside, making it impossible to dry out the crawl space.

Wet Crawl Spaces Have A Higher Concentration Of Unmanaged Moisture.

Wet crawl spaces are just like damp crawl spaces, only worse. Wet crawl spaces face the same moisture problems as damp vented crawl spaces. So, what’s the difference?

  1. Wet crawl spaces have a higher concentration of moisture than damp crawl spaces.
  2. Wet crawl spaces have multiple contributors causing unmanaged moisture.

A wet crawl space could have either or both of these issues going on. The more moisture exists in the crawl space, the more involved the solution to fix it will be.

A simple way to determine whether you’re dealing with a wet or damp crawl space is to look at the floor. You likely have a wet crawl space if you have standing water issues. A professional contractor can visit your home to evaluate the state of your crawl space more clearly.

Once you know what’s going on in your crawl space, how do you fix it?

First, Address The Groundwater In Your Crawl Space.

If you have standing water in your crawl space, infiltration is probably coming from somewhere. Groundwater infiltration can come from several sources.

  1. A negative grade in your landscaping, directing water toward your crawl space
  2. Downspouts not piped away from your crawl space
  3. Groundwater entering through your crawl space floor
  4. A lack of drainage around your home’s foundation

This groundwater infiltration must be addressed before any steps can be taken in the crawl space. You or a professional will need to identify the cause of the groundwater infiltration and solve that problem.

Once the additional source of moisture has been dealt with, your vented crawl space will be damp instead of wet. There are more steps to fixing your crawl space for good.

Next, Treat Any Mold Or Mildew In Your Crawl Space.

In a wet crawl space, mold and mildew are almost guaranteed. Mold must be treated. This problem cannot be ignored. Even if you think no mold exists in your crawl space, you need to test for it.

Many homeowners don’t realize that they breathe the air of their crawl space on a daily basis. Air regularly exchanges between your living space and your crawl space. When this air exchange happens, your expensive conditioned air is replaced with icky crawl space air. Not only is this bad news for your energy costs, but breathing moldy air is also bad for your health.

Even if your crawl space has some fiberglass insulation in the ceiling, the fiberglass will still allow air to exchange. Nothing is stopping the crawl space air from infiltrating your home.

Once the additional source of uncontrolled moisture has been dealt with, you must test for and treat any mold. You do not want any active mold spores anywhere in your home.

While there are DIY mold test kits available for sale, working with a professional is always recommended.

Finally, Encapsulate To Solve Remaining Unmanaged Moisture.

After fixing groundwater infiltration and mold, all that’s left is encapsulating the damp, vented crawl space.

For many homes in southern PA, encapsulation and mold treatment are the only steps for fixing a crawl space. A wet crawl space has additional water issues that must be addressed first.

Encapsulating your crawl space closes off the vents in the walls. We spray the walls with closed cell spray foam, which provides a thermal barrier, air barrier, and vapor barrier. No more unmanaged moisture. Not even air can get inside the crawl space.

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

Our encapsulations also include installing and sealing a vapor barrier on the floor. This vapor barrier protects from the natural vapor content below ground. We can’t encapsulate before dealing with standing water issues because a vapor barrier cannot stop liquid water.

Encapsulation will leave your crawl space clean, dry, and accessible. No more holding your nose or crawling through mud to access any plumbing or HVAC below your home.

Do I Have Any Options Besides Crawl Space Encapsulation?

Is encapsulation the only solution for crawl spaces? Or are we only sharing the method that our company uses?

Crawl spaces are generally dealt with in one of three ways.

  1. Vented crawl spaces with fiberglass in the ceiling cavities
  2. Vented crawl spaces with closed cell spray foam in the ceiling cavities
  3. Encapsulated crawl spaces with vapor barriers on the walls and floor

We’ve already established that vented crawl spaces with fiberglass insulation don’t work. But what about insulating your ceiling with closed cell spray foam? Could the air barrier and vapor barrier it provides solve the problem instead?

In some cases, properties with high water columns cannot realistically have crawl space encapsulation. The groundwater infiltration cannot be solved in these instances. It is rare, but for these properties, we recommend insulating the ceiling with closed cell spray foam. Additionally, the crawl space would need significantly increased ventilation.

The ceiling insulation can cut off the icky crawl space air from the home, while the improved ventilation attempts some moisture control.

If you suspect that your home has a high water column and are unsure of how to fix your crawl space, we recommend contacting a professional contractor. Crawl spaces are unique. Sometimes, spray foam in the ceiling isn’t an option due to existing plumbing or HVAC, even if there is a high water column.

In most cases, we recommend the steps we covered in this article. However, it is possible that your home needs a different or more nuanced approach.

The Bottom Line About Fixing Wet Crawl Spaces

Nobody likes crawl spaces. They’re smelly, damp, and a pain to access. While most vented crawl spaces deal with unmanaged moisture, some have multiple sources that create a wet crawl space.

For most wet crawl spaces, the steps are straightforward. Groundwater infiltration must be fixed. Mold must be treated. The damp crawl space can then be encapsulated.

Now that you understand how to approach your wet crawl space, your next step is to:

Alexis Dingeldein

Alexis has been fascinated by spray foam insulation since 2018. When she isn’t thinking about insulation, Alexis is geeking out over storytelling and spreadsheets.