Basement Waterproofing Case Studies: Encapsulating a humid crawlspace in Radnor, PA

Tuesday, May 2nd, 2017 by Margaret Mustin


Our customer called after a long, steadily escalating battle with the standing water in his crawl space. Every time it rained, or the snow melted, the crawl space would fill with water even though there were no visible cracks in the foundation. There was a sump pump in place, but it wasn’t enough to keep up with the sheer amount of water.

We sent system design specialist Sean Cahill out to inspect the crawl space, and what he found was - not shocking, because we see it often in our line of work, but definitely stressful. The ambient moisture caused an aggressive mold problem which had, over time, rotted out one set of joists and support beams and was working its way through another. The relative humidity in the crawl space was 75% and many of the beams were visibly warped and mold-ridden. The crawl space was in trouble.


The first order of business was protecting the crawl space from the elements; with water coming in through the walls and floor, encapsulation was the solution. By using CleanSpace vapor barrier, along with drainage matting, we can isolate the crawl space from anything entering from outside - like water. By creating this barrier and giving the water room to move, we not only protect the crawl space from the elements, we can protect the house from everything happening in the crawl space.

With the crawl space encapsulated, we turned our focus to sealing off as many entry points of water as we could. We installed a vent cover on the crawl space vent to keep humid air from entering.

With the crawl space sealed, we were able to work on getting any stray water out for good. First, we replaced the existing, slow sump pump with a Smart Sump pump, which is designed for crawl spaces. We added a discharge line that would work with the slope of the lawn to keep water flowing away from the house and  prevented backups in the event of a frozen discharge line. Finally, we installed a dehumidifier to take care of lingering ambient moisture and prevent the mold from having resources to grow. On the day the these were installed, before our production crew had even packed up and left the house, the ambient moisture in the crawl space was already down to 61%.

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BQ Basement Systems
525 Bethlehem Pike
Erdenheim, PA 19038