Save Your Basement from the Elements

As the seasons start to change, now is the perfect time to protect your house from the damage of moisture, colder temperatures and pests by encapsulating your crawl space.

By Erin Gregory

Sep 2017

Illustration by Ali Viknyanskiy

This fall, you may be looking to replace your crawl space encapsulation when touching up your home before the colder months. Crawl space encapsulation is a process of sealing the home’s crawl space from the elements. The foundation walls are insulated, and a heavy plastic vapor barrier is installed over the walls and floor of the crawl space. The crawl space vents are also sealed. The crawl space then becomes an additional conditioned space, which requires humidity and temperature control.

A majority of homes in the area are built with a crawl space, says Doug Morrow, Branch Manager for Bolivar Insulation. This saves on initial costs and performs well for many years.

“Few things could be worse than to have a house built out of organic materials on top of a huge moisture source that will almost certainly cause decaying of all materials, and quite possibly mildew, mold and even health issues,” Morrow says.

Any time of year is good to encapsulate the crawl space, says Chris Chindlund, owner of 417 Crawl Space. “There are several advantages to crawl space encapsulation,” Chindlund says. “The big one, for most homeowners, is the reduction in heating costs. The savings can run from 10 to 30 percent or more.”

Another benefit is reduced moisture levels in the crawl space. When moisture levels are lower, mold can’t grow on the home’s wood structural pieces—such as floor joists and even subfloor. Not only is mold a potential health risk, it eventually leads to wood rot. The air quality inside the home should also improve with crawl space encapsulation.

“Crawl space vapor barriers are not a ‘magic bullet,’” Chindlund says. “If you have problems with water leaking into your crawl space, those issues need to be corrected beforehand.” There are several different sources for crawl space encapsulation products. As with any home improvement project, do your research and make sure your home is a good fit for this kind of project.

When planning crawl space encapsulation, there are several things to keep in mind:

1. You never want to fasten vapor barrier or insulation material to the sill plate. There should be a gap of a few inches from the top of the foundation wall. Otherwise, you are providing a protected path for termites, and other insects, to make their way to the wood your home is resting on.—Chris Chindlund, 417 Crawl Space

2. Although there aren't any "red flags" when looking into crawl space encapsulation, it is important to do your research beforehand, just like any other home project.—Chris Chindlund, 417 Crawl Space

3. If you notice any signs or symptoms such as swollen doors and windows, smelly or damp carpets, buckling hardwood floors, condensation or frost on the inside of windows in cool weather, or aggravated or worsening asthma or allergy symptoms, you should contact an expert.—Doug Morrow, Bolivar Insulation