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Close Your Crawl Space Vents, North Carolina!

Open crawl space vents create problems like mold, wood rot, and pest infestations. Learn more about the science behind vents, why they should be closed, and how Dry Pro can help.

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open crawl space vent

Your home is actually a living, breathing thing – only some areas shouldn’t be breathing, namely the crawl space beneath your house.

Many homes throughout North Carolina were built on top of a crawl space that lifts the main structure off the ground. 

Around the Charlotte area, a crawl space is usually 24 to 30 inches high. It is functional in hiding essential-but-not-aesthetically-pleasing elements like HVAC units, ductwork, plumbing pipes, and electrical wiring. 

However, crawl spaces have a major design flaw: open vents. These vents are like a welcome mat for humid air, precipitation, and pests that infiltrate the crawl space and lead to a host of problems. 

In this article, we discuss why your crawl space has these vents and why they should be sealed. 

Crawl Space Vents: Myths vs. Science

Myth #1: “The crawl space needs to breathe, so add vents.”

Science: Recently, foundation experts have found these practices to be harmful and create the exact problems they were supposed to avoid. With a humid subtropical climate, North Carolina experiences near-constant humidity and precipitation. 
Vents bring in hot, humid air, runoff, and pests, which leads to a multitude of problems including mold growth, wood rot, and infestations. With nothing to remove the humid air, vents do not work. 

Until the 1990s, builders lived by the code of constructing crawl spaces with open vents. The vents were intended to let the crawl space “breathe” by allowing for continuous airflow to avert moisture and mold build-up.  
In North Carolina, in particular, crawl spaces used to be built on concrete piers, then enclosed with bricks. 

Myth #2: “The crawl space will be fine with seasonal vents or dew point vents.”

Science: Any vents, whether seasonal or automatic units that sense the dew point, are bad for your crawl space.  

Many homeowners think they can leave the vents open during the summer and close them during the winter or during rainfall. 
Closing the vents alone will not stop water and moisture from getting inside, and then there’s the issue of having to remember to physically close and open the vents. 
Dew point vents open and close based on the dew point. The problem is they stay closed because it’s very humid five months out of the year. 

Myth #3: “I can just close the vents and add a dehumidifier instead of encapsulating the whole crawl space.”

Science: Closing the vents and adding a dehumidifier is a great first step, but these are just pieces of a much larger crawl space repair puzzle. 

While a dehumidifier controls the level of moisture and humidity in the crawl space, it does not remove any existing water, mold, or other dangers. Without waterproofing or encapsulation measures, water can still percolate through the North Carolina clay soil. 

Think of it this way: adding just the dehumidifier would be like if you were to open all your windows while the air conditioner is running. Not only will this drive up your energy costs, but it’s ineffective. 


The stack effect is the natural flow of air in a building from bottom to top. Aided by open crawl space vents, air enters at the bottom of your house (the crawl space), rises up through the structure, and exits through the attic.  

Approximately 50 percent of the air you’re breathing in your home comes from the crawl space. 

To learn more about how problems in your crawl space affect the rest of your house, check out our page detailing the stack effect

To get moisture out, it’s not enough to close the crawl space vents. You also need to make sure moisture and humidity are removed to avoid damage like mold and wood rot. 

This can be accomplished with professionally engineered and installed crawl space solutions.  Here’s how it works: 

  • Interior Drains: Capture leaking water around the perimeter and direct it to a sump pump. 
  • Sump Pump: Collects water and moves it up and out of the crawl space, and away from the home. 
  • Dehumidifiers: Suck humid air out of the crawl space, convert it to water, and direct it to a sump pump to drain out. 
  • Vapor Barriers: Cover crawl space walls and floor to prevent moisture intrusion. 

Keeping Your Crawl Space Vents Closed Saves You a Lot:

Listening to science will save you a lot of things, including:

  • Money – Properly sealing and encapsulating your crawl space may seem like a significant investment at first, but it will pay off over time as it prevents costly damage and repairs. An energy-efficient dehumidifier will help keep costs down, as well. 
  • Hassle – Permanent, professionally installed vent covers that close off open crawl space vents are airtight and secure. You won’t have to worry about going outside or into your crawl space to constantly open or close the vents.  
  • Your Home – Closed vents aid in creating an unattractive environment for mold, moisture, and pests. Without these nuisances, your crawl space will stay dry, safe, healthy, and structurally sound. This translates to a safer and healthier home, as well. 
  • Your Health – Similarly, closed vents remove the negative impacts of the stack effect. Air naturally moves upward through a house, but a sealed and encapsulated crawl space with proper dehumidification allows clean, healthy air to circulate throughout your home instead of unhealthy air with mold spores and allergens. Anyone in your home with respiratory issues will breathe easier. 

Need to Seal Your Crawl Space Vents? Contact Dry Pro Today!

Don’t settle for temporary solutions at big box stores. Invest in proven permanent solutions thousands of North Carolina homeowners have trusted for more than 20 years.  

Here’s what Dry Pro provides: 

Closing your crawl space vents involves more than switching a lever or plugging a hole. For proper sealing and closure, you need durable, airtight vent covers. 

The installation is straightforward, but it’s best to leave this to the professionals. Our team at Dry Pro offers high-quality vent covers that can withstand North Carolina’s heat, humidity, sun, and rain.  

They are also compatible with our other crawl space repair and encapsulation solutions

If you would like to seal your Charlotte or Hickory area home’s crawl space vents and create a safer and healthier home, contact our friendly and knowledgeable team today to book a free inspection and estimate

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