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Crawl Space Encapsulation Cost Calculator (2026)
Enter your crawl space size, pick a liner, and add the extras. See what encapsulation should cost in 2026, line by line.
| Item | Typical |
|---|---|
| 12-mil reinforced liner, sealed seams | $5,100 |
| Seal vents and access door | $600 |
| Crawl space dehumidifier, installed | $1,900 |
Installed prices including labor and materials. Your quotes can differ with site conditions.
Comparing quotes? Check if your encapsulation quote is fair →
Crawl space encapsulation cost by size
“Standard” here means a 12-mil liner, sealed vents, and a dehumidifier. “Premium” adds a 20-mil liner and wall insulation.
| Crawl space | Vapor barrier only | Standard encapsulation | Premium |
|---|---|---|---|
| 800 sq ft | $720 – $1,750 | $3,900 – $8,800 | $6,400 – $14,000 |
| 1,000 sq ft | $900 – $2,200 | $4,500 – $10,000 | $7,400 – $15,900 |
| 1,200 sq ft | $1,100 – $2,650 | $5,100 – $11,200 | $8,400 – $17,900 |
| 1,500 sq ft | $1,350 – $3,300 | $6,000 – $13,000 | $9,850 – $20,700 |
| 2,000 sq ft | $1,800 – $4,400 | $7,500 – $16,000 | $12,200 – $25,300 |
Cost by component
| Item | Unit | Price range | Typical |
|---|---|---|---|
| 6-mil vapor barrier (floor only) | per sq ft | $0 – $0 | $0 |
| 12-mil reinforced liner, sealed | per sq ft | $0 – $10 | $0 |
| 20-mil heavy-duty liner, sealed | per sq ft | $0 – $10 | $10 |
| Crawl space dehumidifier, installed | per unit | $1,200 – $3,000 | $1,900 |
| Seal vents and access door | per job | $300 – $1,000 | $600 |
| Wall and rim joist insulation | per linear ft | $20 – $40 | $20 |
| Interior drainage + sump pump | per system | $1,500 – $4,000 | $2,500 |
| Debris and old insulation removal | per sq ft | $0 – $0 | $0 |
| Mold treatment | per sq ft | $0 – $0 | $0 |
Vapor barrier vs. full encapsulation
A vapor barrier is 6-mil plastic laid over the dirt. It slows ground moisture but leaves vents open and seams loose. A full encapsulation treats the crawl space as part of the house: a 12- to 20-mil reinforced liner covers the floor and runs up the walls, seams and piers are taped, vents and the door are sealed, and humidity is controlled with a dehumidifier.
Liner thickness matters most if you store things or crawl through the space often. 12-mil is the common standard. 20-mil resists tears from foot traffic and is what top-tier installers use.
Signs your crawl space needs work
- Musty smells in the house, especially in summer
- Relative humidity in the crawl space above 70%
- Mold or dark staining on joists and subfloor
- Fiberglass insulation sagging or falling down
- Standing water after rain
- Cold floors, high energy bills, or pests
- Wood rot or soft spots in floors
Fix water before you seal. Encapsulating over standing water traps the problem. If water pools after storms, add drainage and a sump pump first, and fix gutters and grading outside.
What drives the price
- Square footage. The liner is priced per square foot of floor, and wall coverage grows with the perimeter.
- Clearance. Crawl spaces under 24 inches take longer, and some crews charge 20% or more extra.
- Condition. Old insulation removal, debris, and mold treatment add cost before the liner goes in.
- Water. Drainage and a sump pump are the most expensive add-on.
- Region. Encapsulation is most common in humid Southeast states, where competition keeps prices moderate.
Frequently asked questions
How much does crawl space encapsulation cost?
A typical 1,200 sq ft crawl space with a 12-mil liner, sealed vents, and a dehumidifier costs about $5,100 – $11,200, with $7,600 as a common price. A basic 6-mil vapor barrier costs far less, and jobs with drainage, insulation, and mold work can pass $20,000.
What is the difference between a vapor barrier and encapsulation?
A vapor barrier is plastic sheeting laid on the dirt floor. Encapsulation seals the whole space: a thicker liner runs up the walls, every seam is taped, vents are closed, and a dehumidifier controls humidity. Encapsulation costs 3–4 times more but controls moisture far better.
Is crawl space encapsulation worth it?
It is worth it when you have high humidity, musty smells, mold on joists, sagging insulation, or pests. It can also make floors warmer and cut energy bills. In a dry crawl space with no problems, a simple vapor barrier may be enough.
Do I need a dehumidifier after encapsulation?
Usually yes. Once vents are sealed, moisture needs somewhere to go. A crawl space dehumidifier keeps humidity below about 60%. Some homes instead use a small supply of conditioned air from the HVAC system, where local code allows.
How long does crawl space encapsulation last?
A quality 12- to 20-mil liner lasts 15–20 years or more. Dehumidifiers typically last 5–10 years and need filter changes.
Can I encapsulate a crawl space myself?
Many homeowners install a vapor barrier themselves for $0.40–$0.90 per sq ft in materials. Full encapsulation is harder: taping every seam, fastening the liner to walls, and sealing vents in a tight space. Fix any standing water or mold first.