Crawl Space Encapsulation Cost Calculator
What a sealed crawl space costs installed — liner, labor and the add-ons that quotes differ on.
Installed cost
$7,294.32
- Per square foot
- $6.08/sq ft
- Liner (1,702 sq ft with waste)
- $1,021.20
- Labor
- $2,160.00
- Cleanout and prep
- $1,200.00
- Sealed vents
- $450.00
- Dehumidifier
- $1,800.00
- Contingency (10%)
- $663.12
Prices vary widely by market and by what is found under the house. Use this to read a quote line by line, not to replace one.
Insulating the floor above instead? Price it with the insulation cost calculator →
How this is calculated
liner sq ft = (floor + perimeter × run-up) × (1 + waste%) wall sq ft = perimeter × wall height subtotal = liner + labor + each option selected total = subtotal × (1 + contingency%)
The liner is not only the floor, and quotes that price it that way come in low. Proper encapsulation runs the sheeting one to three feet up the foundation wall and fastens it there with a termination bar, so the material figure is the floor plus the perimeter times that run-up. On a 1,200 square foot space with a 140 foot perimeter, two feet of run-up is another 280 square feet — nearly a quarter more liner than the floor alone.
Waste is higher here than in most trades because seams overlap six to twelve inches and every pier has to be wrapped and taped individually. Fifteen percent is a working default and a space full of piers or an awkward shape will beat it. The contingency on top is not padding: crawl spaces conceal what is wrong with them until someone is lying in one, and rotten joists, standing water and abandoned ductwork are all found after the quote.
Cost by crawl space size
| Floor area | Liner only | Liner + labor | Full job with dehumidifier |
|---|---|---|---|
| 600 sq ft | $604.16 | $1,792.16 | $4,927.16 — $8.21/sq ft |
| 900 sq ft | $865.26 | $2,647.26 | $6,112.26 — $6.79/sq ft |
| 1,200 sq ft | $1,121.80 | $3,497.80 | $7,292.80 — $6.08/sq ft |
| 1,500 sq ft | $1,373.79 | $4,343.79 | $8,468.79 — $5.65/sq ft |
| 2,000 sq ft | $1,789.72 | $5,749.72 | $10,424.72 — $5.21/sq ft |
Every figure comes from the same function the calculator runs, at 12 mil liner, two feet of run-up and a 10% contingency, with the perimeter estimated as a square footprint. Note how the last column flattens per square foot as the space grows: the dehumidifier is a fixed cost, so it dominates a small crawl space and barely moves a large one. That is why quotes on small spaces look so expensive by the foot.
Liner thickness and where each one belongs
| Thickness | Material | 1,200 sq ft space | Where it fits |
|---|---|---|---|
| 10 mil | $0.45/sq ft | $765.90 | Smooth floor, no traffic, budget job |
| 12 mil | $0.60/sq ft | $1,021.20 | The usual minimum for a real encapsulation |
| 16 mil | $0.85/sq ft | $1,446.70 | Occasional access, storage, sharp fill |
| 20 mil | $1.15/sq ft | $1,957.30 | Working storage, warranty requirements |
The whole range spans about seventy cents a square foot in material, which on a typical space is a few hundred dollars between the thinnest and the thickest option. Given that replacing a punctured liner means redoing the labor as well, thickness is a poor place to economize — and a contractor quoting 6 mil sheeting is quoting a vapor barrier, not an encapsulation.
Frequently asked questions
How much does crawl space encapsulation cost?
Most complete jobs land between $5,000 and $15,000, which works out to roughly $3 to $8 per square foot of crawl space. The spread is wide because the liner is often the cheapest part: a dehumidifier, a sump pump, wall insulation and mold remediation can each add more than the plastic did. A liner-only job on a dry, clean crawl space can come in under $3,000.
Is encapsulation the same as a vapor barrier?
No, and the difference is most of the price. A vapor barrier is sheeting laid on the dirt floor, often 6 mil, frequently not sealed at the seams or the walls. Encapsulation seals the space as a system: a heavier liner run up and fastened to the foundation wall, taped seams, sealed vents, and usually a dehumidifier to control what moisture remains. One slows evaporation from the soil; the other changes the humidity of the space.
What liner thickness do I need?
Twelve mil is the common floor for a real encapsulation and handles a space nobody walks in. Sixteen and twenty mil are worth the extra where the crawl space is used for storage, where there is sharp rock or debris underfoot, or where a warranty requires it. Ten mil is fine over a smooth floor with no traffic. The price difference across the range is under a dollar a square foot, so thickness is rarely where a budget should be cut.
Do I need a dehumidifier as well?
Usually yes, and it is the single item most often left out of a cheap quote. Sealing the space stops soil moisture and outside humid air, but it does not remove what is already inside or what leaks in, and a sealed space with no drying capacity can hold humidity higher than the vented one it replaced. A dedicated crawl space unit runs $1,200 to $2,500 installed and needs a condensate route.
Should the vents be sealed?
In a modern encapsulation, yes — the whole approach treats the crawl space as inside the building envelope, and open vents defeat it by letting humid summer air condense on cool surfaces. That said, sealing vents changes how the space behaves, and some jurisdictions have code requirements about conditioned crawl spaces. Confirm the local code before sealing, particularly if there is any combustion appliance down there.
Does encapsulation pay for itself?
Rarely in energy savings alone at these prices. The case for it is usually moisture: rot in the floor framing, mold, pests and the smell that finds its way upstairs cost more to fix than the encapsulation did. Where a house has a genuine crawl space moisture problem, this is repair spending, not an efficiency upgrade, and should be compared against the cost of the damage rather than against a utility bill.
Results are planning estimates built from typical price ranges, not quotes. Regional labor rates vary by more than a factor of two, drainage and structural repairs are priced separately and can exceed the encapsulation itself, and sealing a crawl space that contains a combustion appliance has code implications. Get quotes from insured contractors and check local requirements before sealing vents.