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How Crawlspace Air Gets Into Your Home

Think about the air in your home. It seems safe, doesn’t it? After all, you keep your home clean with regular dusting, vacuuming, and other activities.

Would it surprise you to find out that as much as 50% of the air in your home could be coming from your crawl space? Anything that’s currently in your home’s crawlspace, from mold to vermin, could be impacting your home’s indoor air quality.

Crawlspace air isn’t clean, and often it’s unhealthy. Knowing how your home’s air is impacted by your crawl space, and doing what you can to keep your home’s air safe can help you and other members of your family avoid illnesses and chronic conditions.

How Crawlspace Air Gets Into Your Home

The warm air in your home is constantly rising. When warm air rises from the lower parts of your home into the upper parts, this draws air from your crawlspace into the living areas where you spend the majority of your time.

If your home has a crawlspace, it’s almost certainly impacted by air from below. Just how much air enters your house from your crawl space, and what the quality of that air is like, depends on how well-sealed your crawlspace is.

Crawlspace Air Quality

Crawlspace air can be negatively impacted in many ways, depending on the condition of your crawlspace and what’s happening inside it. Below are some factors that can impact your crawlspace air quality.


Crawlspaces can be wet places. Everything from plumbing leaks to foundation problems can lead to moisture in your crawlspace. Cracks in your foundation can allow water to enter your crawlspace, especially when it rains and during freeze/thaw cycles.

Moisture in the crawlspace can lead to humidity in the home. Your home’s HVAC system may or may not help you manage that humidity. While you can use a dehumidifier to control humidity in your home, this problem will be ever-present as long as there is moisture in your crawlspace.


Where there is moisture, there’s potential for mold. Condensation on the underside of your crawlspace can lead to a variety of problems, including mold growth on features beneath your crawlspace, and on the underside of your home’s subfloor. Mold can cause wood to rot over time, which can lead to other structural problems.

Mold spores that enter your home can cause everything from health problems to strange odors. Mold spores float through the air in your home and may cause mold growth in other parts as well.

Wood Rot

Wood rot (or wood decay) is typically caused by a combination of excessive moisture and fungi.  Excessive moisture within a crawlspace leads to high moisture content within the wood materials, which are the ideal conditions for the growth of wood-eating fungi.  This fungus is different than the other various molds that are also commonly found within wet crawlspaces.  If left untreated, the floors can buckle and break, taking the joists and everything they support with them.


Unfortunately, crawlspaces tend to be warmer than the outdoors, which makes crawlspaces, especially attractive areas for rodents. Rodents also choose to live in the crawlspace because it offers easy access to other parts of the house, where they can access food and water.

Vermin have their own odors and diseases, so when they’re living in your crawlspace, you may start to notice a mysterious animal smell in your home.

Loss of Energy

The air in your crawlspace may be several degrees colder than the air in the rest of your home. When the air in your crawlspace is exchanged with the air in your home, your home’s HVAC system must work harder than necessary to keep the air in your home a comfortable temperature.

Health Side Effects

There are many health effects that can occur when the air from your crawlspace enters the air in your home. Mold spores, for example, can produce allergens that cause allergic reactions.

When this happens, some people experience hay fever symptoms while others experience respiratory distress. Runny eyes, runny nose, skin rash, and other symptoms are all common due to exposure to mold. For people who have asthma, exposure to mold can cause an asthma attack.

How to Protect Your Home from Crawlspace Air with Encapsulation

There are many things you can do to protect your home from exposure to crawlspace air, but an encapsulation of your crawlspace is an effective way to ensure that your home’s crawlspace has better air quality and reduced air exchange between your home’s interior and crawlspace. Encapsulation controls humidity in your crawlspace reduces the temperatures and helps to seal your crawlspace from vermin.

What Is Encapsulation?

Encapsulation is the process of wrapping and sealing your crawlspace to protect it from moisture, humidity, and more. During the encapsulation process, materials like antibacterial vapor barriers are used to seal and wrap your crawlspace, once and for all.

How Does Encapsulation Work?

  1. Assess the status of the crawlspace. Contractors will inspect your crawlspace and draw up a quote commensurate with the work to be performed.
  2. Prepare the area. Mold, mildew, leaks, and more must be eliminated from your crawlspace before encapsulation.
  3. Install vapor barrier. Once the space is ready, vapor barriers are installed to seal your crawlspace.
  4. Insulation installation. After vapor barriers are installed, the crawlspace is insulated.

Other Benefits of Encapsulating Your Crawlspace

Encapsulation does more than simply protect your home from crawlspace air.

  • Protect your home. Encapsulation prevents structural problems by preventing wood rot and corrosion under your home.
  • Improves energy efficiency. Encapsulation keeps your home’s interior more energy-efficient, thus saving you money and preventing extra wear and tear on your home’s HVAC system.
  • Increases the value of your home. Encapsulation increases your home’s value.

Think You Need Crawlspace Encapsulation? Contact Carolina Foundation Solutions

At Carolina Foundation Solutions, we help homeowners in North and South Carolina by conditioning crawlspaces to prevent leaks, moisture intrusion, and more. We improve your home’s indoor air quality. Schedule a free inspection today.

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