Controlling moisture under a home with a small crawl space.
GBA Editor
| Posted in General Questions on
The house was built in 1925 in SW Florida (Fort Myers) with traditional floor joists, sub-flooring, and hardwood floors. There has always been a moisture issue under the house, mold and rotting joists. There is about 2 1/2 feet of crawl space; previous owners had put sand down and a humidistat controlled fan drawing air out of one of the vents in the foundation (approx 12″ x 20″) What else can be done to prevent future damage?
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Replies
There should be a vapor barrier such as poly sheeting; it may already be present below the sand. The real problem, though, is that the fan and vents are bringing air into the crawlspace that is holding more moisture than the air already in the cooler crawlspace. The more the fan runs, or the longer the vents are open, the more moisture condenses in the crawlspace, causing mold and rot.
The best way (in my opinion) to solve the problem is to create a fully conditioned crawlspace. That means insulated, air-sealed walls and either a stand-alone dehumidifier or a connection to your whole-house air conditioning system.