Opening or Closing Vents – Which Way to Go?

Closing your crawl space vents is the right and sensible thing to do, although local codes encourage otherwise.

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Not many homeowners see their crawl space vents as a threat to their homes. After all, it’s a small fixture on the side of the crawl space wall. Nobody checks it or interferes with it most of the time. So, it must be of little to no consequence, right? Wrong. Your crawl space vents can impact the conditions of your home and the below-the-ground area. 

Vents are conduits for moisture-laden air. Other than letting in air, vents also let pests and wood-damaging insects into your crawl space. All these can hurt your crawl space and negatively impact the living conditions in your home. We urge you to reconsider your decision to use these fixtures. 

close your crawl space vent

What Do Local Codes Say?

For many years, codes have encouraged homeowners to ventilate their crawl spaces to regulate moisture and accompanying problems. Codes say venting is a good thing. However, they also say people can close theirs. Whichever route you take, you will have to meet some conditions. 

Our position is firm. Seal the vents because there’s no way you’ll be able to control moisture buildup if these fixtures remain open. We appreciate that the original idea behind venting was to promote aeration. However, venting gets in the way of keeping your crawl space and home dry. You stand to gain by covering them. 

Why You Should Avoid Crawl Space Vents

Studies and tests in many homes show that venting is detrimental in many ways. But the biggest downside is that vents let in moisture during summer months when humidity is high. The continuous flow of moisture-laden air bumps humidity levels and triggers a myriad of problems. Unless you close these fixtures, you will have little control over crawl space moisture. 

Your number one concern should be condensation. It happens when warm outside air sweeps across cool crawl space surfaces — in this case, your walls and floor. Moisture droplets will form as the outside air loses water, setting the stage for mold growth, wood rot, heavy staining, and rust. If condensation goes unchecked, water may pool on the crawl space floor. 

As time goes, the damp air will weaken your wooden structures. Beams and joists will decay and fail to provide adequate support to your home. You’ll be staring at expensive repairs if you let the problem linger. 

Did you know that more than 50% of indoor air originates from the crawl space under your home? Depending on the size of the crawl space, you could see between 10-15 gallons of moist air per day. That’s roughly one gallon per 100 square feet. Rising into your home, this air will force you to run your HVAC unit a lot longer. 

A lot of the air that comes through the crawl space is toxic or filled with pollutants. It can contain dander, dust mites, mold spores, and the smell of decaying wood. Continued inhalation could make you and your loved ones sick. Family members with breathing problems will be affected badly. 

And then there’s the effect of upward-moving air on your home. It creates a stack effect, which means your floors and walls will feel colder. You may have to run your heater even longer to warm up the home. This results in higher heating costs. 

Cover the Vents for a Drier Home

We can place airtight vent covers over the vents to prevent this outside air and moisture from infiltrating your crawl space and even make it more difficult for pests to get inside. If the crawl space has a dirt floor, we can install a heavy-duty 20-mil plastic vapor barrier over it to block surface moisture from seeping into and evaporating in your crawl space. You can dehumidify this space as well. 

Winston-Salem, NC, homes with sealed crawl space vents outperform those with open vents in many ways. Not only are these homes dry, but structurally sound and energy-efficient. Their air quality is better and they have little to no mold. Humidity levels stay significantly low, which is what you aim for as a homeowner. For a free crawl space repair and quote, get in touch with the experts at Tar Heel Basement Systems in Winston-Salem, NC. We’ll help you seal the vents and encapsulate your crawl space so it remains dry, clean, and mold-free all year long.