Research results indicate that a sealed crawl space is a great moisture control strategy with impressive energy saving potential, as reported by Advanced Energy.
As opposed to what many building scientists believed years ago, new research has shown that vented crawl spaces create the perfect environment for mold growth, wood rot, insects and moisture problems.
A sealed crawl space is the perfect defense against these detriments, and has proven to also create a healthier living environment and reduce energy costs.
We met this homeowner at a home show, where they asked us to come to inspect their crawl space because they were interested in encapsulating it due to moisture and mildew-mold concerns. This section of the crawl space is under an addition. The vapor barrier is unsealed, allowing moisture to rise from the ground and contribute to high relative humidity. Microbial growth is beginning on the floor joists and the fiberglass insulation is beginning to sag and fall.
The old materials have been removed, vents sealed, and the sill plate and rim band have been sealed as well. The CleanSpace vapor barrier has been installed with all seams overlapped and sealed. The moisture barrier is also run up the walls 6-8 inches above outside grade. The walls are prepped for spray foam insulation to be applied.
As the insulation acts as a sponge, it holds moisture against the wood joists raising the moisture content of the joists. Mold requires organic material, warm temperatures, and relative humidity above 60% to grow. Often we see mold growing on the paper backing of the insulation and on wood joists in the crawl space. As the moisture content in the joists increases, the probability for wood rot becomes more likely. Once the joists reach 19% moisture wood rot begins. An antimicrobial called Shockwave is sprayed onto the joists to kill the mold. Once the encapsulation is complete and the dehumidifier is installed it will be set to turn on before the humidity in the crawl space reaches 60% (The ideal point for mold to grow). The Encapsulation system will help prevent ideal conditions for mold to grow from occurring and make the home healthier and more comfortable.
Initially, this crawl space was encapsulated with a 6-mil vapor barrier and R-11 vinyl faced fiberglass insulation. Thhomeownerer contacted us with concerns about an ammonia, or animal urine odor in her home and poor air sealing.
Our goal was to remedy the Home Owner’s concerns of foul odors in her home and wasted energy. To achieve this, we installed a 20 mil Clean Space Vapor Barrier on the floor of the crawl space and around the piers. We installed Foamax board insulation on the walls leaving a 3-inch viewing strip for pest control companies to do their inspection. We applied spray foam insulation to the rim and band and sill plate to create an air seal and reduce drafts coming into the crawl space. Finally, we installed a Sani Dry Sedona Dehumidifier, the leading dehumidifier on the market, to pull any moisture that enters the crawl space out.
Since the natural airflow in a home is from bottom to top, the air that is circulated back into the home from the sealed crawl space will be clean, dry air, creating a healthier environment.
Additionally, the air circulating back into the home is now conditioned air, reducing the need to heat or cool it, resulting in lower energy costs.