Insulating and Sealing a Crawl Space in Williamsburg, VA
Challenge
This homeowner in Williamsburg, Virginia called The Drying Company to discuss moisture issues within their crawl space. We sent over one of our trusted professional home performance advisors to evaluate the problems and provide the homeowner with solutions.
We saw a 6-mil vapor barrier lining the crawl space floor, which was torn in many places. Much of the dirt floor was exposed, allowing moisture to rise from the earth and affect the relative humidity. Puddles were found in many places and the liner was covered in debris and fiberglass.
Efflorescence was visible along the foundation walls of the crawl space, a clear indication of moisture infiltration. Efflorescence occurs when moisture seeps through the foundation walls, bringing along with it the inner salts and sediments to the surface, creating a chalky and powdery substance on the walls. There were also open vents lining these walls, allowing the outside air and moisture to freely enter and affect the relative humidity and environment of the crawl space.
We noticed mold and mildew growth on many areas of the floor joists. For mold to grow on any organic materials, such as wood, paper, etc., the relative humidity needs to be above at least 60% with warm temperatures.
We also noticed that the fiberglass insulation was sagging from the floor joists and was quite saturated with water. Chunks of waterlogged fiberglass littered the dirt flooring of the crawl space along with other debris. The insulation acts as a sponge and absorbs much of the moisture, which causes it to become heavy and tear apart.
With the homeowner concerned about these issues and the copious amount of moisture within the underbelly of their home, we drew up some solutions to address these problems and turn their crawl space into a clean, dry, and conditioned space.
Solution
The first thing we addressed was the damp and sagging fiberglass. We needed to clear the floor joists of the insulation so we could tackle the mold and mildew problem. We removed all the fiberglass batts and cleared the crawl space of the existing vapor barrier and all debris littering the floor.
After we cleared everything, we used an antimicrobial, called Shockwave, to eliminate the mold growth on all organic materials. It is important to note that unless the relative humidity and environment are controlled and regulated, the mold and mildew growth can return.
The next thing we focused on was properly covering the crawl space floor. We needed to help protect the crawl space from the moisture rising from the earth, so we installed a heavy-duty 20-mil CleanSpace vapor barrier. This 7-layer polyethylene liner, much like a pool liner, was placed over the dirt floor, wrapped around all piers, and mechanically fastened to the foundation walls six to eight inches above outside grade. Any seams were sealed using special vinyl tape. The CleanSpace comes with an antimicrobial built into it, called UltraFresh, to help reduce mold and mildew growth on the liner itself, giving better protection.
Once the CleanSpace was installed, we moved on to the foundation walls and open vents lining them. Our team placed precisely cut foamboard pieces into the interior side of the vents and sealed them with foam. Once we finished with the vents, we covered the walls with an R10 value of closed-cell spray foam, which acts as an air barrier and vapor retarder. This helps to significantly reduce any outside influence from seeping through these walls and affecting the crawl space. A two-inch viewing strip is left at the top of the walls for termite inspectors.
Now that the crawl space was sealed and protected, we needed to get the relative humidity under our control. A SaniDry Sedona dehumidifier was installed to regulate the humidity and help circulate dry air around the crawl space. A hygrometer device is given to the homeowner, which will allow them to always monitor the temperature and relative humidity of the crawl space.
The homeowner can now feel at ease knowing that their crawl space is better protected from moisture any outside influence. If you are experiencing any of the same issues, then please contact us at The Drying Company. We supply free estimates and excellent solutions to any of your crawl space needs. Let us help you keep the outside, outside!
