Updated November 2, 2026
Key takeaways
- Most jobs cost $3–$7 per sq. ft., and severe ones can reach $10 per sq. ft.
- Totals usually fall between $1,500 and $15,000, with an average near $5,500.
- A dehumidifier adds about $800–$2,000 installed.
- Drainage is separate, and it comes first if you've got standing water.
The typical crawl space encapsulation cost is $1,500–$15,000 in total, with an average near $5,500. Per sq. ft., most jobs run $3–$7, and severe ones can reach $10.
Size sets the starting point, but condition decides the final number. A dry, open 1,000 sq. ft. space costs much less than a low, muddy one with rotten wood and old insulation to haul out.
Access matters as well. A crawl space with a 12-inch opening and 18 inches of clearance takes far longer than one you can nearly stand up in. Ask each company to measure, not estimate from your home's listed square footage, since the two can differ a lot.
Crawl space encapsulation cost by size
Crawl space encapsulation cost mostly follows your square footage. Here's what the usual per-foot range works out to:
| Crawl space size | Typical range |
|---|---|
| 500 sq. ft. | $1,500–$3,500 |
| 1,000 sq. ft. | $3,000–$7,000 |
| 1,500 sq. ft. | $4,500–$10,500 |
| 2,000 sq. ft. | $6,000–$14,000 |
These are typical ranges, not a quote. Your exact price depends on what we find at the inspection.
What's in the price
The price covers five main things. When you compare estimates, make sure each of these shows up, since these are the lines that get skipped when a bid looks oddly low.
- Liner. Thicker plastic costs more. Moisture barrier for crawl space cost depends on the mil rating and how well it gets sealed.
- Vent and rim joist sealing. This one's mostly labor, and it's easy to skip when nobody's watching.
- Wall insulation. Foam board on the walls instead of fiberglass between joists.
- Dehumidifier. Figure $800–$2,000 installed, and sizing matters.
- Cleanup. How much does crawl space cleaning cost? It's often rolled into the job, and more if there's old insulation, debris or animal waste.
If you'd like the how and why behind each part, read about crawl space encapsulation before you collect bids.
Be careful with bids that only quote a price per square foot, with no list of what's included. Two companies can use the same number and deliver very different jobs.
Cost of waterproofing a crawl space
The cost of waterproofing a crawl space is separate from sealing it, and you'll only need it if liquid water's getting in. Interior drainage usually runs $600–$1,800, and a sump pump adds $1,000–$2,500 installed.
So the cost to waterproof crawl space areas comes down to perimeter length and pump needs. Here's more on how getting the water out from under your house works. If you aren't sure if you've got a water or a humidity problem, see why your crawl space gets wet.
Extra repairs that change the total
Extra repairs can add a lot to the total, and they're better found now than after the liner goes in. These are the usual ones:
- Mold treatment. Often needed on joists before sealing.
- Rotted wood. Beam replacement runs $1,500–$6,000.
- Support jacks. Crawl space support jacks cost $300–$1,000 each.
- Termite treatment. Have a pest company clear it first and write down what they did.
Is a cheaper vapor barrier good enough?
Sometimes, yes. A loose 6 mil sheet slows ground moisture, and it costs little. In a dry climate with a space that already tests fine, that might be all you need.
It isn't the same as sealing. Thin plastic tears when anyone crawls over it, and it does nothing about humid air coming through the vents. A 12 to 20 mil liner that's taped and fastened holds up for many years, and it comes with a real warranty if the company offers one. Want a ballpark first? The foundation repair estimator covers moisture problems too.
Encapsulation cost questions
Is crawl space encapsulation worth the cost?
It's worth it when humidity stays above 60% or you've got mold, musty smells or damp wood. You're protecting the framing and improving the air upstairs. If your crawl space tests dry all summer, spending this money probably won't change much, and a hygrometer can help you find out.
How much does a crawl space dehumidifier cost to run?
Usually about what a small household appliance costs. It depends on your local electric rate, the unit's wattage and how often it runs, which is mostly in humid months. A sealed space helps, since the unit isn't drying air that keeps coming in through open vents.
Can I encapsulate my crawl space myself to save money?
You can, and materials cost less than a full job. The tough parts are sealing every seam and fitting the liner around piers while lying on your side. Skip the drainage or wood repair first and you'll trap the problem under plastic. Handy, patient homeowners can do small spaces.
Does encapsulation lower energy bills?
It often does, especially in humid climates, but the savings vary a lot. Sealing vents and insulating walls means your ducts and floors sit in milder air. We won't promise a percentage, since your home's insulation and HVAC setup matter more. The dehumidifier also uses some of those savings.
How much does it cost to convert a crawl space to a basement?
It's a far bigger job than encapsulation, and it's usually priced by an engineer and a general contractor. You're digging out under a standing house and building new walls. We don't do conversions. For most homeowners, sealing the crawl space solves the moisture problem for a small part of that money.
How much do crawl space support jacks cost?
Steel support jacks usually cost $300 to $1,000 each, installed on a proper footing. The total depends on how many supports the beam needs and how tight the space is. Some encapsulation jobs need several, and it's smart to do this work before the liner goes down.
How much does a crawl space moisture barrier cost?
A thin 6 mil sheet is cheap and you can install it for a few hundred dollars. A sealed 12 to 20 mil liner, taped and fastened to the walls, costs more and gets priced as part of the $3 to $7 per square foot range for full encapsulation.
Run into a term you don't know? This may help: foundation repair glossary.