Why crawl spaces stay wet in Tallahassee
Hot, humid air. The Florida building code lists Leon County as a warm, humid climate. A building science guide for these places explains what happens. Warm, wet outside air comes in through the vents. Under the house it cools down. Cooler air cannot hold as much water, so moisture lands on wood, pipes and ducts.
The AC pulls the moisture up. In summer the house is cool and dry, and the crawl space is warm and damp. That same guide says moisture moves from the crawl space up toward the cool house through the floor. Vinyl and other plastic-type flooring can trap it in the wood.
Rain and clay. Tallahassee gets close to 60 inches of rain in a normal year, the National Weather Service says. North of the Cody Escarpment, soils like the Orangeburg series have sandy clay below the top layer. Clay drains slowly, so rain that runs toward the house can sit in the crawl space for days.
Shade and old houses. A local home inspection guide says older Tallahassee neighborhoods like Myers Park, Indianhead and Lafayette Oaks have many homes on raised piers with vented crawl spaces. It says live oak shade slows drying after rain. It also lists leaks under kitchens and baths, wet subfloors and fallen insulation as common finds.
