Crawl Space Encapsulation: Is It Worth It?

Many homes in Georgia, the Carolinas, Tennessee and Virginia sit over a crawl space. In humid summers, outside air brings moisture in through the vents, and the bare ground below adds more. The result can be mold, rot, pests and a musty smell in the house above.

Signs your crawl space has a moisture problem

• Musty smell in the house, especially in summer
• Soft, bouncy or cupping wood floors
• Mold or white fuzzy growth on joists
• Insulation falling down or wet
• Standing water after rain
• More bugs, termites or rodents
• High humidity indoors even with the AC on

What encapsulation includes

1. Fix water first. Gutters, grading and, if needed, a drain and sump pump for standing water.
2. Vapor barrier: a thick plastic liner (often 10 to 20 mil) covering the ground and running up the walls, sealed at the seams.
3. Seal vents and gaps so humid outside air stays out.
4. Dehumidifier or conditioned air to keep the space dry.
5. Insulation: often moved from the floor above to the crawl space walls.

Benefits

• Less mold and musty smell
• Protects floor framing from rot
• Fewer pests
• Can improve comfort and lower humidity in the house
• A clean, dry space for storage and repairs

Is it worth it?

If you have clear moisture problems, encapsulation usually is. If your crawl space is already dry with a good ground cover, a simpler vapor barrier and good drainage may be enough. A careful inspection should tell you which.

Questions to ask contractors

• Where is the moisture coming from, and how will you fix the source?
• How thick is the liner and how are seams sealed?
• What size dehumidifier, and where does it drain?
• Are there termite inspection requirements to keep? Some areas require an inspection gap along the wall.
• What is the warranty?

Frequently asked questions

Should crawl space vents be open or closed?

In humid climates, open vents often bring in more moisture in summer. Encapsulated crawl spaces are sealed and dried mechanically.

Will encapsulation fix existing mold?

Mold should be treated first. Encapsulation keeps it from coming back.

Post your crawl space job with photos and compare bids from local pros.