Crawlspace Encapsulation

It used to be that crawlspaces were just that part of your house you ignored. They were pretty much useless space, being too damp to store things in, full of cobwebs, and darkness. But, today's homeowners are more informed of the dangers and negative impacts of excess moisture in these areas of their home.

Crawlspace Encapsulation

Studies show that nearly half of the airflow in your home can come through your crawlspace. That's 50% of the air you breathe, coming through the moist air that builds up from the ground--this can even happen if there is a concrete floor. Crawlspace encapsulation can be a great solution to this problem. It keeps the moisture out by creating a vapor barrier against unwanted moisture, improving air quality and increasing energy savings as well.

What is Crawlspace Encapsulation?

At its simplest form, crawlspace encapsulation is covering all the surfaces of your crawlspace with a heavy-duty polyethylene barrier. This includes the ceiling (floor joists) above, the walls, support pillars, and floor (which is often either concrete or bare dirt.) Sealing tape is used along all joints between plastic sheets to form a water-tight barrier both to the outside and the living space above.

After the entire area is sealed off, the next step is conditioning the air. This is typically accomplished through the use of a dehumidifier to reduce and regulate the moister in the crawl space.

This combination of both a barrier and dehumidification results in greatly reduced moisture in the crawlspace and all the issues that come with it.

Why Crawlspace Encapsulation?

Too much water vapor and moisture in your crawlspace can cause several issues in your home. Because moisture travels through the porous material of your home almost like a sponge, the flooring, carpeting, and drywall, can have a near-continuous state of dampness to it. This almost always results in some if not all of the following issues:

  • Mold and mildew growth (which can cause serious health issues)
  • Musty smells in your basement and home
  • Increased cooling costs due to running the air conditioning more to try to pull the moisture from the air.
  • Wet insulation in the walls
  • Sweating windows (which can also lead to rotting wood frames.)
  • Insect issues.

Crawlspace Encapsulation Benefits

The benefits of crawlspace encapsulation are many, including:

  • First and foremost eliminating any health concerns associated with mold growth
  • Increased air quality throughout your whole home
  • Reduced costs to heat and cool your home
  • A dry crawlspace is much less likely to have insect problems
  • Potential damage to your home from rot and mildew growth is reduced

Crawlspace Encapsulation Considerations

Making sure your crawlspace encapsulation job is done correctly is key. Hiring a company with little experience, or trying to do it yourself, could end up with a lot of money and effort going to waste. Or worse yet cause issues that could be costly, or even dangerous. Water will find a way, so even an incorrectly sealed seam could negate all the work done. Before a crawlspace encapsulation project is begun, consider the following issues:

  1. Major Water Issues - Encapsulation is useful for general dampness issues. It's not intended to address foundation waterproofing needs. If water is pooling in the space or flowing through the walls, this needs to be addressed separately.
  2. Insect Infestations - Before sealing off your crawlspace, you must first make sure any insect issues are addressed. Especially if you have a termite problem. Encapsulating the space will make it much harder for pest control companies to do their job.
  3. Potential Backdrafting - If there is any combustion equipment in the crawlspace, such as a furnace, or water heater, it will be necessary to vent these to the outside to keep any gases from building up in the space. This is definitely an area where you'd want to have the professionals do the work for you.

How Crawlspace Encapsulation Works

This simple step-by-step guide will walk you through what you can expect when encapsulating your crawlspace. Each location is different, but the steps are all just about the same.

  1. Preparing the Space - It's important to thoroughly clean out the space to be encapsulated. This means removing anything that may be stored in the crawlspace. It's also a good idea to look for sharp objects that might tear the plastic during installation, including rocks in the dirt floor (if there is one) staples, or nails, or any other area that might snag the material.
  2. Measure and Cut the Material - Getting proper measurements are key. The fewer seams you have, the better. It is a good idea to light the space well, and definitely use the old measure twice, cut once adage. It is recommended that the vapor barrier material is cut outside of the crawlspace, to allow for easier measuring and straighter lines. The material will need to be cut larger than the area measured to allow for an overlap of each piece when taping.
  3. Vapor Barrier Installation - The goal is to have a completely sealed unit when done. It is important to try to keep the vapor barrier smooth, and flat against the surfaces. This is accomplished by adding double-sided tape to the bottom of the floor joists, and the corners of the walls. The plastic should be firmly pulled tight, eliminating as much as possible, any wrinkling of the fabric. Then pressed tightly onto the surfaces of the crawlspace.

Why Use A-1 for Crawlspace Encapsulation?

  • Trained professionals with experience with a variety of spaces
  • Multi-year warranty on every crawlspace encapsulation job
  • No job is too large or too small
  • Locally Owned and Operated
  • Supported by our National A-1 Franchise Network
  • A-1 is a fully insured contractor


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