Resealing a Williamsburg, VA Crawl Space
Challenge
A homeowner in Williamsburg called us out to investigate their crawl space, which they say has had moisture issues. We sent out a Home Performance Advisor to inspect the crawl space and found that there were indeed signs of past moisture infiltration, such as muddy trails and puddles in certain areas of the crawl space. We also noticed that there were gaps in places where their existing vapor barrier meets piers and the foundation walls. This can allow the earth's moisture to rise into the crawl space and affect the relative humidity, leading to mold growth and further moisture damage to materials. It was evident to us that there must have been a lot of groundwater beneath the existing liner. We also noticed that the homeowners had existing foam boards mechanically fastened and sealed to their foundation walls. This may help to insulate the crawl space, but the earth's moisture and outside influence will still need to be sealed off properly. Open vents lining these walls were also allowing the outside air and moisture to freely enter the crawl space, where it could raise the relative humidity and affect the environment. Our advisor quickly drew up a proposal to help mitigate the effects that moisture had on this crawl space.
Solution
The first thing we did was remove the existing vapor barrier and any debris littering the crawl space floor, then we installed a drainage system under the crawl space grade level using a 4" perforated corrugated sock pipe with drainage rocks. This drainage system was then connected to a Super Sump Pump system, which contains a 1/2 horsepower Zoller pump and a discharge line that leads to a predestined area behind the home. Then we installed a durable 10-mil vapor barrier, called CleanSpace Light, over the dirt floors of the crawl space. We wrap the vapor barrier around all piers and mechanically fasten it to the foundation walls six to eight inches above outside grade. This will help to protect the crawl space from moisture rising from the earth. CleanSpace will resist wear and tear, and it comes with an antimicrobial, called UltraFresh, built into the material. This will help mitigate mold and mildew growth on the liner itself. We then turned our attention to the open vents lining the foundation walls. Custom foam board pieces were used to block the open vents on the inside and then sealed with foam. This will cut off the free flow of outside air and moisture to the crawl space. Normally, we would then move on to adding spray foam or Foamax foam board to insulate the foundation walls, but the homeowner decided to keep their already existing foam board insulation. Insulating and sealing the foundation walls blocks off the moisture that is seeping through the porous walls, and helps to control the temperature and environment of the crawl space. The last thing to add is a high-performance dehumidifier, called SaniDry Sedona. This dehumidifier will help to control the relative humidity and temperature of the crawl space, and it will circulate dry air around the space. A hygrometer is given to the homeowner to monitor the relative humidity and temperature of their crawl space. Annual maintenance and inspections are scheduled, and the homeowner can now enjoy a dry and comfortable crawl space underneath their home. If you are also experiencing high energy bills, musty odors, or an uncomfortable home, then please give us a call at 1-757-566-8622. We'll help you keep the outside, outside!
