Skip to Main Content
condensation in crawl spaces

Condensation in Crawl Space

Crawl space condensation can lead to unhealthy conditions such as mold growth and structural instability. Learn what causes this issue and how you can address it.

Schedule Free Inspection

Condensation in Crawl Space: Problem Signs

Damaged insulation

Condensation in crawl space is a sign that you have a moisture problem. In general, condensation forms when the relative humidity in your crawl space reaches 100%. In other words, this is the point when the air can’t hold moisture any longer.

Condensation in crawl space can then lead to a number of problems, such as mold and mildew growth. Furthermore, the unhealthy air circulating through your home can cause health problems for your family. Nevertheless, there are proper ways to eliminate the issue altogether.

What Causes Condensation in a Crawl Space?

In particular, venting causes crawl space condensation. In this case, the open crawl space vents let outside air into your crawl space. As a result, moisture is created when the indoor air combines with the outdoor air.

For example, if your crawl space is 65°F and the outside air is 95°F (with a relative humidity of 70%), there’s a temperature difference of 30°F. For every degree the air’s cooled, the relative humidity goes up by 2.2%. So, when the different temperature airs combine, the relative humidity will increase by 66%.

If you add the 66% of newly created humidity to the 70% of the 95°F air, there will be a relative humidity in your crawl space of 136%. The air can only hold moisture up to 100% so that humidity will be given up as condensation. Specifically, wall vented crawl spaces contain liquid water, moisture vapor, and fungal spores.

“Specifically, wall vented crawl spaces contain liquid water, moisture vapor, and fungal spores.”

Crawl Space Condensation Solutions

In fact, numerous studies have concluded the best way to stop condensation in your crawl space is to seal or encapsulate it.

“Houses built on closed crawl spaces will be notably drier, support less mold growth, and surprisingly are more energy-efficient than houses built over vented crawl spaces.”

Encapsulation involves completely sealing your crawl space from outside elements. First, a thick vapor barrier, like CrawlSeal, will be laid on top of the floor and up the walls. In addition, a three-inch inspection gap will be left near the sill. This should always be implemented so pest control companies can inspect for termites and other pests.

Any outside openings, like vents and loose doors, will be sealed. In general, this will prevent outside air from entering your crawl space and contributing to the problem. Moreover, sealing your vents will help solve various moisture issues in your crawl space.

Benefits of Crawl Space Encapsulation

  • Minimizes mold growth
  • Can save you 15-18% on your energy bills
  • Improves your indoor air quality

We’re Experts in Crawl Space Repair

Are you looking for local crawl space contractors in Virginia, DC, Maryland, or Northeastern North Carolina? If you would like a free quote, we’re ready to help you! Call or e-mail us today to schedule an on-site consultation and written quote! We’re here to help you find the perfect solution for your home, and find out the source of your crawl space repair problems.

    Contact Us For Your Free Inspection

    * All fields are required.

    Publish Date:

    Last Modified Date:

    Service Areas


    8361 Town Center Ct
    Nottingham, MD 21236


    311 Central Rd.
    Suite 2-02
    Fredericksburg, VA 22401

    Hampton Roads & NE NC

    2569 Quality Ct
    Virginia Beach, VA 23454

    Northern VA & DC

    7940 Gainsford Ct.
    Bristow, VA 20136


    309 Quarles Rd
    Ashland, VA 23005

    Southwest Virginia / Roanoke

    2033 Cook Dr.
    Salem, VA 24153

    Western Virginia

    456 Old Courthouse Rd
    Appomattox, VA 24522


    45 W Boscawen St,
    Winchester, VA 22601