Price guide · updated October 2026
Crawl space encapsulation and repair costs around Knoxville
Typical installed prices for encapsulation, vapor barriers, dehumidifiers, drains, sump pumps and crawl space supports in East Tennessee, what moves them, and a calculator to ballpark yours. They are typical ranges, not our price list — your real number comes from a free on-site estimate.
Typical prices
Crawl space prices by service
Installed prices, labor and materials, for homes around Knoxville. Each service links to the page that explains how the work is done.
- Full crawl space encapsulation
- $5,000–$12,000
A complete system: a sealed heavy liner on the floor and up the walls, vents and access closed, and a dehumidifier. About $5–$10 per square foot; large or wet crawl spaces that need drainage first can pass $15,000.
- Vapor barrier only
- $1,500–$4,500
About $2–$4 per square foot installed, for a reinforced liner overlapped, taped and sealed at the piers. No dehumidifier.
- Crawl space dehumidifier
- $1,000–$2,500
A crawl-space-rated unit sized to the space, installed with a continuous drain line.
- Crawl space insulation
- $1,000–$3,500
About $1–$4.50 per square foot depending on the type: rigid foam board, spray foam or batts. Removing failed insulation adds to it.
- Interior French drain
- $25–$35 / linear ft
In a dirt-floor crawl space. A 100–150 ft run is about $2,500–$5,250 before the sump pump; rock and tight clearance add to it.
- Exterior French drain
- $3,000–$6,500
About $30–$90 per linear foot depending on depth. Putting the lawn and beds back is usually extra.
- Sump pump installation
- $800–$2,000
A new basin, pump, check valve and discharge line. A battery backup adds about $150–$250.
- Sump pump repair
- $300–$600
Float switch, check valve or a blocked discharge. Replacing a worn-out pump runs $700–$1,600.
- Underground downspout line
- $200–$2,000 per downspout
Piping a downspout underground to a discharge point down the slope. A simple extension or gutter fix is often a few hundred dollars.
- Regrading around the house
- $1,000–$3,300
Bringing back the slope that sends rain away from the foundation instead of toward it.
- Crawl space support jacks
- $1,000–$1,600 each
Adjustable steel supports on new footings. Adding 2 to 5 under a girder is about $2,000–$8,000.
- Sealing foundation vents
- $150–$450
For a typical crawl space, about $40–$50 per vent installed. Replacing a broken vent runs $100–$250 each.
Ballpark it
Crawl space cost calculator
Pick the job and put in the size. The range updates as you type.
Typical installed range
$6,000 – $12,000
Full encapsulation, 1,200 sq ft at $5–$10 per square foot.
What moves the price
Six things that decide what your crawl space costs
- 01
The size of the crawl space
Liner, tape and labor scale with the square footage. The dehumidifier and the setup cost about the same for a small space as a large one, so small jobs cost more per square foot.
- 02
Water already getting in
Standing water means drainage, and often a sump pump, before anything is sealed. Sealing a liner over water just hides it.
- 03
Clearance and access
Labor is 50 to 70 percent of an encapsulation, so a crawl space you can kneel in costs less to work in than one you have to lie flat in.
- 04
What has to come out first
Old plastic, failed insulation, debris and anything stored under the house all add time before the new work starts.
- 05
The ground under the house
Limestone close to the surface limits how deep a drain can go and adds digging time. Hillside lots and high water tables change where the water can be sent.
- 06
The system you choose
Liner thickness and wall coverage, the dehumidifier’s size, the type of insulation and a battery backup for the pump all move the number.
Not sure what the ground under your house is doing? Find your town — its page explains the ground under it.
By service
How each kind of work is priced
Waterproofing
Stop water getting in, and move the water that is already there back out.
Drains $25–$35 / linear ft · sump pumps $800–$2,000
Waterproofing questionsCrawl Space Encapsulation
Seal the ground off, then keep the air under there dry for good.
$5,000–$12,000 for most crawl spaces
Crawl Space Encapsulation questionsCrawl Space Repair
Steel supports on proper footings, sealed foundation vents and an access door that closes — the parts of a crawl space that fail first.
Steel supports $1,000–$1,600 each
Crawl Space Repair questions
Cost questions
Questions about crawl space prices
Are these Waterproofit TN’s prices?
No. They are typical installed ranges for crawl space work around Knoxville, drawn from local and national cost guides and checked in October 2026. They are here so you know roughly what to expect before anyone comes out; your actual price comes in writing after the free on-site estimate.
Is crawl space work more expensive in Knoxville?
Not noticeably. Published Knoxville ranges for a complete encapsulation, $5,000–$12,000, sit inside the national ranges, where the average is about $5,500. The bigger differences come from the house itself: how much water, how much rock, and how tight the crawl space is.
Why is labor such a big part of the price?
Because most of the work is done kneeling or lying in a space two or three feet high. National cost guides put labor at 50 to 70 percent of an encapsulation, and tight clearance, debris and old insulation to haul out push it higher. The liner, tape and even the dehumidifier are the smaller share.
Why can two encapsulation quotes be thousands of dollars apart?
Because encapsulation is not one product. One quote may be thin plastic on the floor, another a reinforced liner sealed up the walls with the vents closed, a crawl space dehumidifier and drainage. Line them up on liner thickness and coverage, vents and access, the dehumidifier, drainage and the written warranty, and the gap usually explains itself.
Does a bigger crawl space cost less per square foot?
Usually. The dehumidifier, the setup and the trip cost about the same whether the space is 800 or 1,800 square feet, so larger crawl spaces tend to land lower per square foot. Very tight or very wet spaces are the exception.
Is it cheaper to fix the gutters first?
Often, and it is worth doing first. If the water comes from a downspout dumping against the wall, an extension or an underground line at $200–$2,000 per downspout can be most of the answer, against several thousand dollars for a drain. We check that before we quote drainage.
Financing, deposits and the free estimate are covered on the FAQ page.
Get a real number for your crawl space
A free on-site estimate takes about an hour: we go under the house, take readings, and you get a written price before anyone starts.