Experienced Crawlspace Moisture Control Experts in Bohannon, VA

This Bohannon, VA new homeowner contacted us because they wanted their crawl space encapsulated. At the inspection, we found that there were bulk water concerns, evidenced by staining and erosion around the perimeter of the foundation walls. There was also mold and mildew growth on the floor joists. The existing vapor barrier was damaged and missing in many places and was not preventing moisture from the earth from impacting the environment in the crawl space. The existing fiberglass insulation had been absorbing moisture in the crawl space and holding it against the floor joists. The added water in the insulation was making it heavier and causing it to fall away from the floor.

Moisture infiltrates a crawl space through vents, around the crawl space door, through gaps in the home’s construction such as the sill plate rim and band, utility penetrations through the block wall and the ground. All of these points allow water vapor in and once moisture is in the crawl space, it’s trapped and wreaks havoc.

To encapsulate the crawl space and control the groundwater, we proposed that the homeowner first opt to have any old insulation, vapor barrier and debris removed and treat the mold and mildew growth with an antimicrobial.

Then we suggested installing an interior foundation drainage system with a sump pump. The system would be installed around the perimeter of the crawl space and direct the collected bulk water to the lowest point of the crawl space, where our proposed TripleSafe Sump pump would evacuate any collected water to a spot designated by the homeowner on their property and away from the home.

We then recommend installing a heavy-duty CleanSpace 20-mil vapor barrier, that is overlapped and sealed at all seams, wrapped around all piers and sealed, and fastened and sealed to the crawl space walls about 6 inches above outside grade. This will completely isolate the crawl space from the earth’s moisture.

Then we would seal all penetrations in the foundation wall, such as utility penetrations. The sill plate and rim & band will also be sealed with foam to stop outside air from pouring into the crawl space and help reduce drafts in the living space. We would seal the crawl space vents from the inside with foam board insulation and foam to both insulate and prevent air from entering the crawl space. By sealing vents from the inside, we can maintain the aesthetic of the exterior of the home.

We then suggest that the homeowner insulates the crawl space walls with Rigid Foam Board insulation or Closed Cell Spray Foam. This will extend the thermal envelope of the home which can not only make the home more comfortable but will make floors warmer in the winter, and reduce energy bills.

Finally, we recommend installing a SaniDry Sedona Dehumidifier. We have done everything we can to prevent outside air carrying moisture and vapor from the earth from infiltrating the crawl space, however, we need to ensure we are controlling the relative humidity so that we do not see microbial growth return and protect the home’s structure. The Sedona is specifically designed to work in crawl spaces and cuts only when it is needed. It maintains the relative humidity of the crawl space preventing it from rising over about 55% so that we do not reach the 60% relative humidity that allows microbial growth. The unit is designed to pull excess moisture from the crawl space environment and circulate dry air to keep the entire space dry.

If the homeowner chooses this approach for their crawl space encapsulation, they will achieve an improved indoor air quality, warmer floors in the winter, lower energy bills, fewer drafts, and their home will be healthier and more durable.