This is the Right Way to Encapsulate Your Crawl Space

Most crawl spaces are dark and wet. They also harbor biological contaminants (mold), pests, or both. These conditions compromise the durability and efficiency of your HVAC equipment, water heater, and other components that reside below your home. They can also create serious indoor air quality problems.

Long story short: Your crawl space environment impacts the comfort of your indoor environment. Thankfully, crawl space encapsulation can improve both.

But you have to do it right.

What is crawl space encapsulation, anyway?

Crawl space encapsulation refers to the process of dividing the area below your home from your actual living space, or building envelope. When done correctly, it prevents the passage of air from the crawl space to your living environment and creates healthier living conditions.

Your crawl space also goes from looking like this:

Dirty Crawl Space

To this:

Encapsulated Crawl Space

The benefits? Floors will be cooler in the summer and warmer in the winter. Your HVAC equipment will last longer. You’ll save on energy bills. You’ll reduce opportunities for mold or pests to enter your home. There’s a lot to love about an encapsulated crawl space.

Unfortunately, not everybody does it right.

Here’s how NOT to improve your crawl space

Before showing you the right way to encapsulate your crawl space, let’s a look at a few things you shouldn’t do to improve your crawl space environment:

  • Add a vapor barrier… and nothing else: Halfway improvements are common, but they’re not effective. A plastic vapor barrier on the floor of your crawl space might reduce humidity coming from the wet earth below, but it’s not going to insulate a vented crawl space from the humid outdoors.
  • Ignore poor waterproofing or mold growth: If you have standing water and/or mold growth in your crawl space, encapsulation is Step 2, not Step 1. You need to deal with those problems first.
  • Dehumidify a vented crawl space: You can’t dehumidify a space that’s open to the outdoors. If you try, the dehumidifier will run 24/7 with zero reduction in crawl space humidity.

These are just examples of failed crawl space improvements that we’ve encountered in Atlanta-area homes. Total encapsulation is the only way to truly transform your crawl space into a clean dry environment that’s conducive to healthy indoor conditions.

Here’s how to do it right:

Step 1: Mitigate all drainage, mold, or combustion problems.

Some crawl spaces aren’t ready for encapsulation. Before you opt to encapsulate, be sure your crawl space isn’t suffering from:

  • Inadequate drainage around the foundation: Insufficient grading or a poorly maintained drainage system allows water to seep into your crawl space. If you see standing water beneath your home, contact a structural engineer or drainage company before pursuing encapsulation.
  • Mold growth: When you have mold growing on your floor joists or HVAC equipment, you need to clean it up before an encapsulation project traps it inside your crawl space.
  • Backdrafting from combustion appliances: At PV, we always perform a safety inspection before encapsulating your crawl space. One reason we do this is to identify whether a gas furnace or water heater is emitting carbon monoxide. Encapsulating a crawl space with leaky gas appliances can allow harmful gases to backdraft into your home.

The good news is that most homes don’t have any of these problems! After verifying that you’re in the clear, you can proceed with encapsulation.

Step 2: Completely seal the floor, vents, and walls.

You want to seal your crawl space from your home envelope and, to the extent possible, the outdoors. To make that happen, you’ve got to do all of the following:

  • Add a plastic vapor barrier to the crawl space floor and attach it to the foundation walls, piers, and equipment. Attaching the vapor barrier helps keep moisture out of your crawl space. In addition to walls and piers, we also attach the vapor barrier to your air handler or water heater – whatever it takes to seal off crawl space components from the ground below.
  • Seal off all vents and openings to the outdoors. We want to prevent humid outdoor air from entering your crawl space. To make that happen, we seal off crawl space vents using foam board and spray foam. We also attach foam board to the crawl space door.
  • Add a thermal barrier to the crawl space walls. To further prevent outdoor air from entering your crawl space, we attach foam insulation to all crawlspace walls.  
  • Air seal all the gaps and cracks. The next step is to seal off all remaining gaps and cracks with spray foam: Band joists, AC drain line runs, plumbing penetrations, wiring, etc. This step includes sealing all gaps between the crawl space and the floor of your home. PV is an Icynene dealer, so we can use Icynene closed cell spray foam when needed.

When we encapsulate crawl spaces, we always maintain a continuous point of inspection to satisfy termite regulations. That way, nobody has to dismantle the encapsulation to inspect for termites.

Step 3: Keep the crawl space dry.

Completing the above steps will go a long way toward keeping your crawl space clean, dry, and unappealing to insects and other pests. However, moisture barriers, air barriers, and thermal barriers alone aren’t always enough to maintain low humidity levels year-round. For that, you’ll need to install a drying mechanism.

At PV, we install a dehumidifier in every encapsulated crawl space. These devices, which are sized to fit your crawl space, drain directly to the outdoors. We also install humidity monitors, so you can actively keep tabs on the effectiveness of your dehumidification equipment!

Crawl spaces don’t have to be scary.

Encapsulated crawl spaces don’t smell bad. They’re dry. They protect your water heater and air handler components. They’re inhospitable to insects.

Basically, they’re not scary! Changing the temperature on your water heater doesn’t have to mean battling camel crickets, inhaling mold spores, or hoping you don’t get bitten by a spider.

Most importantly, an encapsulated crawl space prevents biological contaminants from entering your living environment. Thanks to improved indoor air quality, you and your family will be breathing a whole lot easier.

If you’re ready to encapsulate the crawl space in your Atlanta-area home, contact PV today for a free consultation!

Image credits: Alpha and PV Heating & Air