Case Studies

Crawl Space Moisture Control Case Studies: Fixing Cold Floors and High Energy Bills in Toano, VA

Tuesday, April 20th, 2021 by Erin Dougherty


This Toano, VA homeowner contacted us after receiving several energy bills for their new home. They had previously lived in a larger home in Yorktown, VA, and had lower energy bills than they do in their new, smaller home. In the colder months, their bills were nearing $300 even though they were keeping their thermostat at 68 degrees and their home never felt warm, especially on the first floor. They had their HVAC unit evaluated and it was functioning properly, as well.

One of our Home Performance Advisors met with this homeowner to discuss their concerns, do a thorough inspection of the home, and develop the right solution to help them get their energy bills under control.

Our inspection led us into the crawl space of the home. We wanted to focus on this area because we knew that the first floor being too cold was a concern and cause of discomfort to our clients. We also know that the stack effect causes air to escape out of the top of the home, and new air to be sucked in at the bottom to replace it. This creates a bottom-to-top airflow in your home. To learn more about the stack effect watch this video: The Stack Effect & Your Home

Open vents have been allowing outside air, which is cold in the winter and hot and humid in the summer, to flood into the crawl space and become trapped. This cold air makes the floors upstairs colder not only making it uncomfortable, but it also costs more to heat and cool the home. In warmer months air is humid and damp air uses more energy to heat and cool.

Exposed earth also allows moisture to rise into the crawl space and contribute to the high relative humidity in the space. All this humidity in the space does not just make it more difficult to heat and cool the air, but it also causes damage to the insulation, can allow mold and mildew growth on the floor joists and paperback of your insulation, and negatively impact the indoor air quality of the home.


To address our client’s concerns about high energy bills and the first floor being uncomfortable, we began by addressing the problems in the crawl space.

First, we cleaned the crawl space of the existing fiberglass insulation, vapor barrier, and debris. Then we used an antimicrobial called shockwave to kill the mold and mildew growth on the wood substructure of the home.

To help reduce the energy consumption of heating and cooling the home, we wanted to seal the crawl space from outside influence. This is achieved by first sealing the crawl space from the earth’s moisture with a 20-mil CleanSpace vapor barrier. The liner is laid out on the floor, wrapped around all piers, and attached to the foundation walls 6-8 inches above outside grade. Finally, all seams are sealed. Next, all vents, the rim band, and the sill plate are sealed with foam insulation.

Then the foundation walls are insulated with closed-cell spray foam at an R-10 value. A 2-inch viewing strip is left at the top of the foundation wall, per VA Building Code. This viewing strip allows for termite inspectors to do their inspections. A friction-fit interior crawl space door was installed behind a new, Everlast exterior crawl space door. The friction-fit door provides an R-10 of insulation and air sealing behind the exterior door. The Everlast Crawl Space Door is a PVC door that is designed not to warp, rot, or rust.

The final step in controlling the humidity in the crawl space, or how damp the air is, is to install a dehumidifier. For this, we used the SaniDry Sedona Dehumidifier. This unit is designed to pull excess moisture from the air, filter it, and circulate dry air throughout the crawl space. A Hygrometer is installed with a sensor in the crawl space and a base unit in the home. The base unit displays the temperature and humidity both in the crawl space and inside the home. This allows our homeowners to monitor the conditions of their crawl space.

This system will prevent as much outside air and moisture from infiltrating the crawl space as possible and control the humidity. This means that the homeowners will not be spending as much to heat and cool their home, their floors will be warmer in cooler months, and they can be more comfortable in their home.

our service area

We serve the following areas

Our Locations:

The Drying Co./ThermalTec
236 Industrial Blvd
Suite A
Toano, VA 23168

The Drying Co./ThermalTec
Mailing Address
P.O. Box 637
Toano, VA 23168
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