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How To Manage Crawl Space Humidity In Your Home

Extreme crawl space humidity can lead to various problems that might impact the health and structural integrity of your home.

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A properly constructed crawl space should be dry and free of moisture. Otherwise, water in the crawl space can lead to several issues, including mold, rot, and pest infestations. Moisture can also affect your indoor air quality and lead to costly structural damage. To maintain a healthy crawl space, it is vital for Fargo, North Dakota, homeowners to keep humidity levels in this space at an optimum. 

insulated crawl space

When is crawl space humidity too high? 

When warm outdoor air enters your crawl space, it gets cooled and condenses, raising the relative humidity. Relative humidity refers to the amount of water content in the air in relation to the maximum amount of water the air can hold at a certain temperature. High relative humidity can lead to the growth of mold, wood rot, pest infestation, and energy loss.  

Effects of high humidity on your crawl space 

A high crawl space humidity leads to the following issues: 


High humidity levels in the crawl space create an ideal environment for mold to grow. As the mold grows, your home may suffer structural damage. The mold spores will also provoke allergies and sinuses. 


Moisture in the crawl space leads to rot. Rot in the crawl space causes the floors above to sag, leading to uneven floors. In extreme cases, some sections of your floor may start to cave in. 

Pest infestations 

Moisture in the crawl space also attracts pests. Your open vents and cracks in the wall will allow pests to enter and damage your structure. 

Structural damage 

The walls in your crawl space are a prime site for condensation. Moisture fluctuations will cause the concrete to expand and contract, and this can lead to cracks. The excess moisture can also cause irreversible damage to your hardwood floors, window and door frames, and other wooden fittings. 

When is Crawl Space Humidity Too Low? 

Just like high humidity levels can impact the health of your crawl space, so can a low humidity level. Although it is impossible to dry out a crawl space, you can make it much drier than it already was. Naturally, buildings, whether old or new, require a certain amount of moisture level to run effectively. This level is used as an acclimation guideline.  

So when the long-term moisture level changes in the crawl space, the wooden features installed in the past can behave differently, leading to several issues. For instance, when relative humidity levels go below 30% the wooden components in the crawl space can dry out and start to shrink. This can damage your furniture, floors, and window panes.  

Generally, wood requires a certain amount of moisture to maintain its integrity. When the moisture content goes below five percent, the wood starts drying out and weakening. As a result, you may start seeing your wooden floors and beams buckling and bowing, which isn’t a good thing. Therefore, to maintain a healthy atmosphere in the crawl space, you need to maintain a humidity level above 30 percent. This will help keep the wood moisture content between five to 12 percent.  

What is the Ideal Crawl Space Humidity Level? 

The ideal relative humidity level should be kept and maintained between 30 and 50 percent all year round. This will help deter mold growth, wood rot, and pest infestation.  

How to Maintain Optimal Crawl Space Humidity 

The best defense against humidity in the crawl space is encapsulation and a dehumidifier. Let’s look at both solutions in detail. 

Crawl space encapsulation 

It’s one of the effective ways of controlling humidity levels in the crawl space and can stop water intrusion. We’ll first install air-tight covers on the vents and seal leaky crawl space doors before applying the plastic vapor barrier on the crawl space. Our waterproofing experts will cover the floors and walls with a 20-mil plastic barrier. What this does is cut off outside air and moisture. 


A dehumidifier is a great finishing touch for drying out your space and helping you preserve the integrity of your home. At Innovative Basement Authority, we pride ourselves in providing our clients with innovative crawl space dehumidifier systems. Each of our units is rated for energy efficiency and powerful enough to remove any excess vapor from the air to keep everything dry and safe. 

If keeping your crawl space dry and healthy is at the top of your priorities, contact Innovative Basement Authority today to schedule a free crawl space inspection and receive a free quote on dehumidifier installation.

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We service Minnesota, North Dakota, South Dakota and Eastern Montana for basement waterproofing and crawl space repair.

Fargo, ND

1330 41st St. N
Fargo, ND 58102

Minneapolis, MN

6265 Carmen Ave.
Inver Grove Heights, MN 55076

Rush City, MN

1325 S Frandsen Ave
Rush City, MN 55069

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101 S. Reid Street, Suite 307
Sioux Falls, SD 57103