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Should I Dehumidify My Crawl Space

Many homeowners are asking, "Should I Dehumidify My Crawl Space"? Many contractors are saying all you need are fans to control humidity in the crawl space. What's the best solution to controlling humidity in the crawl space? We recommend a minimum of three things that every crawl space located in a humid environment requires.

1. Properly Installed Vapor Barrier

The ground in the crawl space, no matter the soil type, will allow moisture to enter. Clay soils, sandy soils, or a mix have moisture in them and this moisture eventually evaporates into the crawl space.

A loose laid vapor barrier is all that is needed for an open or vented crawl space. But once you decide to seal the crawl space, code requirements change. Sealing the crawl space is a great way to control humidity in humid areas when done properly.

2. Sealed Vents and  Dehumidifier

Sealing the crawl space vents causes the code to change when it comes to the vapor barrier. But sealing vents does not require you to install a crawl space dehumidifier. This is what I mean by doing it correctly. In humid areas, sealing the vents alone does not seem to work effectively at constant humidity control. This is why a crawl space dehumidifier is always recommended. But wait, sealing all the vents could cause an unforeseen issue.

3. Install a Foundation Vent Fan

I know, I just blew your mind! Yes, we recommend installing a foundation vent fan with properly installed vapor barrier and crawl space dehumidifier. Technically, the vent fan is not used to control humidity, so you could leave it out of the equation. According to the EPA, the foundation vent fan helps control odors and soil gases that build up in the crawl space. When you properly install all three, the humidity will be controlled and soil gases should be kept in check.

What Next?

Do you need help with crawl space dehumidifiers or encapsulation in your home, and you live in Georgia, Delaware, North Carolina, South Carolina, Tennessee, or Kentucky? If so, please contact us to schedule your assessment. Also, let us know in the comments below if you'd like to suggest a future blog post.

Perhaps you'd like to tackle your own crawl space repair. Visit our DIY Store.

Contact us if you need help fixing your crawl space or yard drainage by clicking here.

Learn about Crawl Space Ninja Franchise opportunities.

About Michael Church

Michael Church has been involved with indoor air quality since 2005 and feels the unhealthy crawl space is one of the major problems causing poor indoor air quality.


  1. Jerry Butler on April 3, 2022 at 3:38 pm

    Enjoyed your videos but I have somewhat unique condition. I have crawlspace within a crawlspace. It actually had a hot tub which I have remove. This space is walled of from the rest of the crawlspace, i.e. four cinderblock walls. I have put down a vapor barrier and fully insulated the interior walls. I would like circulate air from the house through this space in order to primarily control humidity and to some extent temperature. I’m planning on installing a motorized floor vent and an exhaust fan to pull conditioned air from inside the house. My problem is finding a wireless monitor to control the vent and circulation fan. I have found a wireless system that monitors temperature and will turn on an outlet but can’t find a setup that also monitors humidity. Actually humidity is my primary concern as all of the walls in this space are interior walls. The surrounding crawlspace is gravel with plastic sheeting which is very common for the area of southern Maryland. Would very much appreciate any suggestion on a wireless controller to activate the power?

    • Michael Church on April 5, 2022 at 1:01 pm

      Jerry I apologize but am unaware of anything currently that could help you. I will keep my eyes open and if I come across something, I will let you know.

  2. George on October 8, 2023 at 10:39 am

    What are your preferred 2000 square foot crawl space dehumidifiers?

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