Crawl Space Vapor Barrier Cost
A vapor barrier is one of the cheapest ways to cut crawl space moisture; full encapsulation costs more but seals the space completely. Enter your crawl space area to compare DIY, professional installation and encapsulation.
Last reviewed September 2026
Liner at $0.40–$0.60 per sq ft with a 15% allowance for overlaps and wall coverage, plus labor at $1–$2.50 per sq ft. Standing water, mold or wet insulation must be fixed first and add to the cost.
Vapor barrier and encapsulation prices
| Job | Typical cost |
|---|---|
| 6-mil liner (materials), per sq ft | $0.05–$0.20/sq ft |
| 20-mil liner (materials), per sq ft | $0.40–$0.60/sq ft |
| Professional labor, per sq ft | $1–$2.50/sq ft |
| Full encapsulation, per sq ft | $3.35–$10/sq ft |
| Full encapsulation, most homes | $5,000–$15,000 |
Water standing in the crawl space? Deal with that first: see water in crawl space.
Vapor barrier questions
What's the difference between a vapor barrier and encapsulation?
A vapor barrier is a plastic liner over the dirt floor to block ground moisture. Encapsulation seals the liner to the walls and piers, closes the vents and usually adds a dehumidifier, turning the crawl space into a dry, conditioned space.
What thickness of vapor barrier should I use?
6-mil is the minimum and fine for crawl spaces you never enter. Thicker liners (12- to 20-mil) resist tears from foot traffic and are the usual choice for encapsulation.
Can I install a crawl space vapor barrier myself?
Yes, if the crawl space is dry and you're comfortable working in a tight space. Overlap seams by at least 6–12 inches, tape them, and run the liner up the walls. Fix standing water or plumbing leaks first.