A. Bruce Davis, senior building science specialist at Advanced Energy in Raleigh, N.C., responds: Before beginning work to dry out a crawlspace, there should be a discussion and agreement (ideally, in writing and signed) between the contractor and the homeowner about the potential for house shrinkage as a result of solving the moisture problem. The next step is to confirm that there is not a liquid moisture problem. Is there a live spring, a plumbing leak, a surface drainage problem, or a hydrostatic source for liquid moisture?
Once those potential moisture sources are removed, you will probably want to seal the crawlspace vents. In the Southeast, outside summer air generally holds more moisture in vapor form than the air in the crawlspace does. When this outside air enters a ventilated crawlspace, it can contact a surface cool enough for condensation to form. Any...
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