Insulating a Yorktown, VA Crawl Space
Challenge
We were contacted by this homeowner because they believed their crawl space had been encapsulated incorrectly. At the inspection, we found mold growth in the crawl space, a 6-mil vapor barrier, and vinyl faced fiberglass insulation on the walls that was not sealed on all sides. The 6-mil vapor barrier is not durable enough to withstand people working in the crawl space. It punctures and tears easily allowing moisture from the earth into the crawl space. The Fiberglass insulation on the walls was absorbing vapor that came through the porous block walls and due to not being sealed, it allowed that moisture to enter the crawl space. High relative humidity, warm temperatures, and organic material allow mildew/mold to grow. In the crawl space, we usually see microbial growth on floor joists, sub-flooring, and the paper backing of batt fiberglass insulation.
Solution
Due to the system being ineffective, the homeowner chose to remove all of the old insulation and the 6-mil vapor barrier and start over. We treated the mildew/mold growth with Mold-X2, an antimicrobial and Botanical that kills the mold and removes staining. We then re-encapsulated with a 10-mil vapor barrier sealed to the walls and all seams overlapped and sealed. The 10-mil will hold up to technicians working in the crawl space. This Crawl Space was conditioned, so it did not have vents to seal. The Foundation walls are insulated with Foamax, a rigid foam board insulation. All seams are sealed to each other and the wall, this creates an air and vapor barrier. As moisture finds its way through the cinderblock walls, it will be directed down beneath the vapor barrier, keeping it out of the crawl space.
