Encapsulate your crawl space with vapor barrier

Seal your crawl space with a 20-mil polyethylene vapor barrier covering the floor and walls, then condition the space with a small dehumidifier. This eliminates the primary moisture source for most homes built over crawl spaces.

Why It Works

Exposed dirt in crawl spaces releases 10-15 gallons of moisture per day into the home. This moisture migrates upward through floor joists, feeding mold growth on subfloor sheathing, insulation, and eventually interior surfaces. A sealed crawl space cuts moisture intrusion by 80-90%.

Steps

1. Remove standing water and debris from the crawl space
2. Seal foundation vents with foam board and caulk — vented crawl spaces in humid climates actually increase moisture problems
3. Install 20-mil vapor barrier (brands: Stego Wrap, Americover) across the entire floor, lapping 12 inches up walls and sealing seams with barrier tape
4. Add a crawl space dehumidifier (Santa Fe Compact70 or AprilAire E080, $800-$1,200) set to maintain 50-55% relative humidity

Tips

• Professional encapsulation costs $5,000-$15,000; DIY materials run $1,500-$3,000
• This single improvement often eliminates musty odors throughout the entire home
• Check for termite inspection gaps required by local code before sealing