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Crawl Space Humidity

Humidity is one of the biggest threats to your crawl space, because it promotes mold growth and breaks down wooden support beams. This problem sign causes structural problems in your home.

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When you think of Texas, humidity might not be the first thing that comes to mind. However, humidity does rise in June, July, and August. If your home is built on a crawl space foundation, this rise in humidity becomes a problem. Humidity in your crawl space is a sign that major damage is just around the corner. Don’t worry, FSS has solutions that keep humidity out of your crawl space. Read on to learn more about this problem sign.

Crawl Space Humidity Explained

In the past, it was thought that building a crawl space with ventilation would allow the space to stay cool. Unfortunately, this is rarely the case, especially in a warm environment like Texas. During summer months outdoor humidity and heat drastically increases. Meanwhile, your crawl space stays cooler because it is completely covered in shade by your home above it.

It’s this difference in temperature that causes humidity to rise in your crawl space. See, cold air holds less moisture than warm air, so when outside air enters your crawl space during the summer, it leads to a sharp rise in humidity. Since it was hot outside, the air was able to hold more moisture. When the hot air mixes with the cooler crawl space air, some of the moisture needs to be released.

This is what causes condensation and rising humidity. Released moisture will be absorbed into wooden structures and concrete walls in your crawl space. Eventually, the rising humidity will lead to mold, wood rot, or sagging floors.

What Causes Humidity in Your Crawl Space?

Crawl Space Vent

Open Crawl Space Vents

When you look at most crawl spaces, you’ll notice open vents along the foundation walls. Back in the day, contractors believed that building crawl spaces with these open vents would allow trapped humidity to escape outside. However, modern day contractors have learned that this design actually makes it easier for humid air to get into your crawl space. Essentially, open vents force your crawl space to emulate the environment outside. When humidity rises outside, it also rises in your crawl space and leads to mold or wood rot.

Soil Washout

You might think humidity can only get into your crawl space through the air, but groundwater can actually contribute to rising humidity. Even though Travis County and Bexar County receive a low amount of annual rainfall, even a little bit of precipitation can cause soil washout in your yard. Simply put, this is when water displaces soil as it drains below the ground. Over time, this groundwater travels below your crawl space, where it evaporates and becomes trapped below your home. This water vapor causes humidity levels to rise and leads to condensation on various surfaces such as pipes, insulation, and support beams.

Leaking Pipes

Most crawl spaces house important systems such as electric wiring, air ventilation, and plumbing lines. Obviously, plumbing lines allow water to travel through your home, but if one of these lines burst, tons of water will flood into your crawl space. If the water is left to sit, it will evaporate and cause humidity levels to rise throughout the foundation. Once again, this contributes to mold growth and structural issues in your home such as sagging floors.


High humidity in any environment, whether a home, basement, or crawl space, can be devastating. Generally, humidity levels in these spaces should be between 30-60 percent, with an optimum goal of 50-55 percent. At these levels, mold, wood rot, and other moisture-related issues have no chance of developing. Moreover, keeping your crawl space within the proper humidity range can also lower utility bills in your home since humid air won’t be traveling up from your crawl space.

The best way to control humidity in your crawl space is with a dehumidifier. You might be tempted to buy a dehumidifier from the store and place it into your crawl space. Unfortunately, there a few problems with using a store-bought brand. One, they simply don’t have the storage capacity to handle humidity below your home. Ranging from 20-70 pints of water removal per day, consumer dehumidifiers aren’t built for crawl space use. 

Moreover, many dehumidifiers need to be emptied by hand. Even self-draining dehumidifiers can end up becoming too full. Taking a trip into your crawl space just to empty water isn’t ideal. Instead, contact FSS to protect your crawl space with an energy-efficient dehumidifier with self-draining mechanisms and the capacity to remove 105 pints of water every day.

Yes. Vapor barriers on their own are an effective way to keep humidity out of your crawl space. Their name implies their function – serving as an impenetrable barrier against water vapor. Keep in mind, using vapor barriers alongside other crawl space solutions guarantees the best possible protection against humidity. FSS can help install a crawl space drain, dehumidifier, and crawl space vent covers that work alongside our 20-mil thick vapor barrier. With these protections in place, your crawl space will be completely protected from humidity.

How FSS Stops Humidity in Your Crawl Space

Protecting your crawl space from humidity ultimately keeps your home healthy and even saves you money by lowering energy bills. There are a few ways we stop humidity from rising below your home. Vapor barriers and vent covers offered by FSS make it impossible for humid air to get into your crawl space. These solutions isolate your crawl space from the outdoor air and keep the environment controlled.

We also offer energy-efficient dehumidifiers that prevent water vapor from building up in your crawl space. Our powerful dehumidifiers remove up to 100 liters of water a day and have self-draining mechanisms for your convenience. Interior waterproofing from FSS is another solutions that quickly removes flooding water from your crawl space. After a storm or internal leak, water can flood your crawl space and eventually evaporate. This also causes humidity to rise, but our waterproofing solutions stop that process before it even starts.

Explore Solutions

Even though rising humidity outside is out of your control, the health and protection of your crawl space doesn’t have to be. With crawl space encapsulation from FSS, your foundation stays permanently dry. Using a vapor barrier, dehumidifier, sump pump, and more keeps the environment below your home completely controlled. Don’t let mold, wood rot, and other problem signs destroy your crawl space any longer with our solutions.

Keep Humidity Out with Help From FSS

Humidity can cause tons of problems for both your home and its foundation. We know what it takes to stop crawl space problem signs from overtaking your home. Since 2017, our neighbors in Texas have trusted us with their crawl space needs. Using high-quality tools manufactured in the USA and a team with over 20 years of combined experience, you can be sure that your crawl space receives the best possible service in the state. Contact us to learn more about crawl space encapsulation and to schedule a free inspection with one of our technicians today!

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