Crawl space encapsulation: what is it and why do you need it? We are going to look at both of these questions, but first, let’s explore the crawl space.

In Knoxville, and East Tennessee, many homes, if not most, have a crawl space; that space between the living area of your home and the ground beneath. East Tennessee is a mountainous region, and homes often sit on uneven ground. A crawl space is the result of the builder creating a level platform for your home to sit on.

Crawl spaces are not necessarily wasted space beneath your home. If the area is large enough and has headroom, some homeowners use it for storage. Most crawl spaces are used for little more than hiding lawn mowers, ladders and such; and for good reason, they are usually small, damp, dirty places.

Dirt floors are the norm for crawl spaces. Conventional wisdom was that the area below the home was not that important; just wall it in and put vents all around so fresh air can circulate allowing the moisture to dry out. You can leave it alone. The problem with this thinking is that it doesn’t work.

The Problems of Crawl Spaces

Air enters your crawl space through the vents around your home, after all, that is what the vents were put there to do. However, the air doesn’t dry out the crawl space and exit through the opposite side air vents. This is wishful thinking. If this did happen, mold would not grow, and your home would be cheaper to heat in the winter and cool in the summer. So what does happen?

Moist air enters the crawl space through open vents around the base of the house. The dirt floor under the home naturally contributes some moisture as well. Even if it is made of concrete, which is a porous material, moisture will enter the crawl space. At this point, your crawl space has become a perfect environment for the growth of mold. It is cool, dark, damp, and has all that wood holding up your home to eat. The question that you should have at this point is, “Why doesn’t the air circulate through the crawl space and out the other vents taking the moisture with it?” Good question. Let’s answer it.

The Chimney Effect

The best way to describe what happens to the moist air entering your crawl space is to illustrate it. Keep in mind, up to 60% of the air in your home comes from the crawl space.

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Chimney Effect Diagram, Tennessee Mold Solutions, LLC

Chimney Effect Diagram, Tennessee Mold Solutions

  1. Water seeps up from the ground into the crawl space. If the floor is dirt, this can be a bigger problem, but as I said before, a concrete floor doesn’t guarantee moisture will not come up through the floor because concrete is porous. If you have pooling water in your crawl space, you definitely need to fix this.
  2. Humid air enters the crawl space through the vents provided by the home’s designer. At this point, you have a crawl space with a lot of moisture on the ground and moisture in the air. Frequently, these conditions breed mold and mold spores get into the moist air. Now the air is contaminated.
  3. Due to the chimney effect, air from the crawl space rises, and enters your home through all the small gaps around plumbing pipes, electrical wires, and such. Even though these holes are usually small, when you add them all together, the hole can be as large as a square foot. That is a lot of contaminated air entering your home. This air brings with it mold spores, odors, and sometimes little critters that populate your crawl space.
  4. The migrating mold spores will find a place in your home and make it their home. Mold spores are microscopic and travel well in moving air. If they get into your home they will attach to any organic material it can find and if the conditions are right, begin reproducing and eating the material it lands on.
  5. Attic ventilation draws the air into the attic and then out of the building. Most homes are built with ventilation systems on the roof to draw air out of the building to keep it cool in the summer. As the air is sucked out, it draws more air from the lower floors of the house, ultimately pulling air from the crawl space.

The moist, mold contaminated air going from your crawl space into your home not only creates a health risk for some people, but it costs a lot more to heat and cool a home that doesn’t have encapsulation, up to 20%.

How Does Crawl Space Encapsulation Help?

Crawl space encapsulation can be quite involved depending on the severity of the problem. However, many encapsulations are straightforward.

First, the area is cleaned of debris and then leveled as much as possible. The walls and the floors of the crawl space are covered with watertight materials to prevent water from entering the space. The vents are also covered to prevent moist air from entering.

Once this is completed, the moist air and water from the ground will no longer have a way into your crawl space. The air will be dry and mold will not have the moisture it needs to grow. In addition, your home will not be as difficult to heat in the winter or cool in the summer. The average cost savings to homeowners is 18-20%.

An encapsulated crawl space is more attractive, cleaner, safer, and cost effective than one without it. Encapsulated crawl spaces can be used for storage just as before, but the area will be cleaner.

If you would like us to come by and look at your crawl space, please give us a call. We will be happy to give you a free estimate.