This was a real estate transaction and the home inspection report showed excessive humidity in the crawlspace due to a non-functioning dehumidifier. This resulted in organic growth in the subfloor, and the exisiting crawlspace liner was off-gassing. There was also an issue with rain run-off from overflowing gutters and seeping into the foundation. The home also tested high for radon, at the average level of 7.6 pCi/l.
We re-encapsulated the crawlspace using a 16-mil liner, removed the moldy sub-floor insulation, remediated the organic growth, replaced with dry insulation, used spray polyurethane foam insulation on the rim joists to seal out moisture, installed Aprilaire 1850 and Aprilaire 1820 dehumidiers, installed a condensate pump to channel the dehumidifer water out of the crawlspace, and installed a sub-slab/sub-membrane radon mitigation system in the basement and crawlspace which brought the radon level down to 0.5 pCi/l. We also finished off the basement with a 16-mil FinishSheild Wall Liner to keep it dry.