Green Design: What’s in your crawl space?
How much time do you spend thinking about your crawlspace? If you are like me, not very much. Just the thought of crawlspaces makes me shudder as visions of what could be in the depths below run through my head. It’s also so confusing concerning what to do with vents: are they open in the fall, closed in the summer? And the radon we have to deal with here in Middle Tennessee, what is that about? Well, we recently spent some time in Beth Haley Design’s crawlspace and we ended up learning a tremendous amount about how the crawlspace can affect the home above it.
This summer E3 Innovate visited the 1930’s home we use as our design office and worked their magic in our crawlspace. E3 offers a signature system and the benefits of it are outstanding! The sealed crawlspace system begins with a three layer antimicrobial plastic with a fiberglass mesh. This plastic is so durable that it will never become brittle and will most likely outlive the structure. It is laid down across the entire space below a home and seams and edges are double taped and sealed. It is then wrapped 12-in. to 18-in. up the sides of the foundation wall.
This provides a clean, continuous liner for the floor of the crawlspace. The foundation above the liner is then covered in spray foam insulation. This sealed system provides the crawlspace with a vapor barrier. A high quality dehumidifier and an air supply vent are used to keep this space conditioned, providing a cool environment during the summer and warm the floors in the winter.
What are the benefits of this system? For starters, the crawlspace is now a clean white surface. Long gone are the days of dirt floors and dark corners. Since it is one continuous white surface, if there should be a leak above, you’ll spot the source immediately. And since we are on the subject of moisture, let’s talk about this system’s main feature—it serves as a vapor barrier. The plastic liner is placed directly on the ground to control moisture from the soil. The liner prevents moisture from evaporating from the soil into your crawlspace. Reduced moisture content in this space allows your cooling system to work more efficiently.
Insulating the foundation walls with spray foam greatly increases control of moisture levels and eliminates the use of the old, itchy, rolled fiberglass insulation. With lower overall moisture content the chance of mold or moisture damage is greatly reduced within the crawlspace and also in the living areas. This also affects the amount of condensation that may be found on ductwork, insulation, and pipes. The reduced moisture level will help keep wood floors from buckling, wood framing from rotting, and lower the humidity throughout the entire house.
Once the moisture is under control, there are other crawlspace issues that this system helps eliminate as well. Musty odors and the number of critters underneath your home is greatly reduced. Now that the crawlspace is sealed, it’s unlikely that the home’s HVAC system will pull contaminates into the ductwork. This reduces the overall amount of dust in a home and gives the home cleaner air.
Last, but not least, is radon control. Radon is an odorless, tasteless radioactive gas that comes from the natural decay of uranium found in the soils and rocks here in Middle Tennessee. Radon is a finicky gas and can be present in low to high ranges from house to house and from year to year.
It is recommended that you test your home for radon every few years. It moves up through the ground and into a home through holes and cracks in the foundation, construction joints, and walls. Long term exposure to high radon levels can be deadly. The EPA estimates that radon is the second leading cause of lung cancer, responsible for about 21,000 deaths a year.
A sealed crawlspace system does not eliminate radon levels, but it does deter it from entering into a home. If high levels of radon are found in a crawlspace, a pipe system outfitted with a fan moves the potentially deadly gas up and out of your home safely.
So when looking at ways to improve a family’s life with a clean, dry, and healthy home, start at the bottom with your crawlspace. Investigate a sealed system that provides a moisture barrier, reduces mold, dust, and radioactive gas, and keeps out insects and mice.
—By Jennefer Guthrie
Editor’s Note: Beth Haley Design, an urban interior design firm, focuses on remodeling and revitalizing established homes, as well as creating stimulating, functional, sustainable spaces in new homes. Jennefer Guthrie is a LEED accredited professional and a member of Middle Tennessee Chapter of USGBC (United States Green Building Council). E-mail your questions to her at firstname.lastname@example.org or visit www.bethhaleydesign.com.