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Foundation Vents – Why They Don’t Work

Foundation Vents - Why They Don't WorkIt’s a common misconception that your crawl space needs to breathe. In the past, it was believed that foundation vents were the best way to get rid of crawl space moisture.

However, we now know that installing foundation vents to air out your crawl space actually creates greater moisture problems.

In addition, an Advanced Energy study found that crawl spaces with open foundation vents stay above 70% relative humidity – well above the healthy humidity level of 50%. If there were open vents – even if a vapor barrier was installed – high humidity continued to be a problem.

Foundation Vents Let Moisture In!

Open foundation vents let outside air into your crawl space, which creates moisture problems.

Moreover, the air in your crawl space is typically cooler than the outside temperatures – with some exceptions. As the warmer outside air combines with the cooler crawl space air, humidity is created.

Here’s how it works: Let’s say that your crawl space is 65°F, coupled with the outside air at 95°F (with a relative humidity of 70%). Notably, that’s a temperature difference of 30°F. For every degree that the air cools, the relative humidity goes up by 2.2%.

For every degree that the air cools, the relative humidity goes up by 2.2%

So, in this example, when the different temperatures are combined, the crawl space humidity will increase by 66%. Specifically, air can only hold up to 100% humidity, after which it will need to release the excess moisture in some fashion.

With the increase in humidity of 66% added to the 70% humidity of the outside air, the total humidity is 136%. To clarify, the air cannot hold this much moisture and, as a result, you’ll end up with crawl space condensation or sweat.

As you can imagine, all of that extra moisture will create issues in your crawl space. In the event that you come across this problem, it’s best to contact an expert right away.

Foundation Vents = Moisture: Your Crawl Space’s #1 Enemy!

Foundation Vents = Moisture: Your Crawl Space's #1 Enemy!

Unless you’re planning on turning your crawl space into a steam room, moisture and humidity should be removed. By all means, the build-up of moisture in your crawl space can become a devastating issue.

Mold, wood rot and mildew all thrive in environments that have over 50% humidity and a food source, like wood floor joists. Sound like your crawl space?

And this is just the beginning…

If you happen to have mold or wood rot in your crawl space, chances are good that insects will be in your crawl space as well. Not only do insects love to eat mold, but also mildew and rotted wood. After all, these pests are just following the easiest food source.

Equally important: what eats insects? Rodents. Consequently, if you have open foundation vents, mice can easily find their way into your crawl space to chow down on the bugs.

As a result, you can see that a moisture problem can end up leading to a serious pest infestation. However, plenty can be done to resolve the issue before or during the infestation.

Foundation Vents, the Stack Effect, and your Crawl Space

Foundation Vents, the Stack Effect, and your Crawl Space As air warms, it rises. The same can be said for the air in your crawl space as well. In other words, this effect is known as the Stack Effect, or Chimney Effect.

In detail, the air in your crawl space warms and will rise through your home, up through the floor joists and boards, and into your living spaces. Furthermore, anything that’s light enough to travel with the air, like humidity or mold, will also travel into the living areas of your home.

So, like it or not, you end up breathing the air – and other stuff – that’s in your crawl space. Gross!

Above all, the best way to stop this cycle is to encapsulate or seal your crawl space. Thus, sealing your crawl space from the outside elements. This process involves installing a thick crawl space vapor barrier over the floor and walls. Additionally, the barrier seals up the foundation vents and door. Also, installing a dehumidifier will greatly reduce moisture.

Want to learn more? Give one of our experts a call at 866-370-4816 to request your free crawl space moisture control inspection.

We’re Here To Help You Find The Best Solutions For Your Crawl Space…

We will work with you every step of the way to make sure that you feel comfortable with your home’s crawl space solution – from inspection and planning to installation and project completion.

Not to mention, requesting your free inspection takes 60 seconds, and you can download your Free Homeowner’s Guide to Crawl Space Repair immediately!

request a free inspection for foundation vents

Are You Looking For Local Crawl Space Contractors In Virginia, DC, Maryland, or Northeastern North Carolina?

At JES Foundation Repair, our team of in-house crawl space experts have warranted solutions for crawl spaces and foundations of all types.

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 proud to serve all of Hampton Roads, from Virginia Beach throughout Williamsburg and surrounding areas; Northern Virginia, DC, and Southern Maryland. View a complete list of our service area here.

The Experts at JES can Help!request a free inspection for foundation vents

If you’re not sure of the source of your crawl space problem, give us a call at 866-370-4816, and schedule a free inspection. We’ll find out the cause of the problem and help you find the perfect solution.

We now have a crawl space to be proud of and feel very secure that we will not have any future problems. Pauline and I will not hesitate in recommending your company to anybody. We thank you for your services.

~ Burt and Pauline S., Williamsburg, VA

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Free Homeowner's Guide to Crawl Space Repair

Our Homeowner’s Guide to Crawl Space Repair is your resource for learning about why you have crawl space problems, and what to look for to see if you have a problem.

Request your free crawl space repair inspection and download your own copy of the e-book immediately, as our thanks for putting your trust in JES.

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