Real ranges, and the reasons they move. Anyone giving you a firm price without going under the house is guessing.
Typical Ranges
Vapor barrier alone — $1,500 to $4,000. A properly specified twelve to twenty mil liner, seams taped, walls terminated, piers wrapped.
Full encapsulation — $5,000 to $15,000. Liner, sealed vents, perimeter insulation and a sized dehumidifier. The national average is around $5,500, which reflects simpler and drier crawl spaces than many houses here need.
Interior drainage and sump — $3,000 to $8,000. Perimeter trench, perforated pipe, basin, pump and discharge.
Sump pump only — $1,200 to $3,500.
Support and structural repair — $1,500 to $6,000 for jacks and footings. Joist or girder repair generally in the low thousands.
Mold treatment — $1,500 to $6,000, and meaningless quoted on its own.
Foundation repair — national average around $5,176, typical range $2,225 to $8,135. Individual push piers $1,500 to $3,500 each, helical piers $2,000 to $4,000.
Basement waterproofing — $5,000 to $12,000 for interior drainage. Wall stabilization $5,000 to $10,000.
What Actually Moves the Number
Clearance, more than anything. Two crawl spaces of identical size can differ by thousands because one has three feet of headroom and the other has eighteen inches. Labor is most of the cost and low clearance slows everything.
Whether water has to be dealt with first. A dry crawl space needing a liner is a different job from a wet one needing drainage before the liner makes sense.
Existing damage. Rot, failed supports and contaminated insulation all have to be handled before sealing.
Debris and access. Old insulation, construction waste and a hatch you can barely get a bucket through all add hours.
How to Read a Quote
Ask for it itemized. Debris removal, drainage, structural repair, liner with the thickness stated, vent sealing, insulation, dehumidifier with model and capacity.
A single number tells you nothing and cannot be compared with anyone else’s single number.
Where Cheap Quotes Cut Corners
Six mil builders’ plastic instead of reinforced liner. Seams overlapped and not taped. Liner stopped at the floor instead of run up and fastened to the walls. Piers left unwrapped. No dehumidifier, or a domestic unit that will not last a summer in those conditions.
Every one of those produces something that looks finished and performs like nothing was done.
The Cheapest Thing That Might Work
Extend your downspouts. Four to six feet clear of the foundation, properly, costs very little and resolves a meaningful share of crawl space water problems outright.
We check that before quoting anything expensive. If it is the answer, we will tell you, and it will not be a job worth our while — which is rather the point.
(256) 270-0146 for a free inspection.