Basement and foundation repair cost calculator
Enter the basement dimensions, what you are seeing and which solution is on the table. You get a range, the assumptions behind it, and the figure a contractor would have to justify.
What each approach actually is
Interior perimeter drain (drain tile + sump)
Break the slab inside, lay perforated pipe in gravel, run it to a sump. Does not stop water entering the wall — it collects it under the slab and pumps it out. Cheapest reliable fix, and the one most national franchises sell.
| Modelled US range | $50–$100 per linear foot |
|---|---|
| Disruption | Inside: slab cut, dust, 2–4 days. Outside untouched. |
| Expected life | Pipe itself: decades. The pump is the wear item — 7–12 years. |
Exterior excavation + membrane + footing drain
Dig to the footing, clean and seal the outside face of the wall, add a drainage board and a footing drain. Keeps water out of the wall instead of managing it after it is in. Two to four times the price.
| Modelled US range | $100–$250 per linear foot |
|---|---|
| Disruption | Outside: excavator, landscaping and hardscape gone, 1–2 weeks. |
| Expected life | Membrane 20–30+ years if backfill is done right. |
Interior sealant / coating only
Paint-on or cementitious coating. Handles vapour and very light seepage. Against hydrostatic pressure it fails — the water finds the weakest point or pushes the coating off. Sold far more often than it works.
| Modelled US range | $0–$0 per linear foot |
|---|---|
| Disruption | Minimal, 1–2 days. |
| Expected life | 3–10 years, less if there is real pressure behind it. |
Carbon fibre straps on a bowing wall
Bonded strips that stop a cracked wall bowing further. They hold; they do not straighten. Suitable up to roughly 2 inches of deflection — past that an engineer needs to look.
| Modelled US range | $450–$950 per strap |
|---|---|
| Disruption | Inside only, 1 day. |
| Expected life | Permanent if the cause of the load is also fixed. |
Steel wall anchor / helical tieback
Ties the wall back to a plate or helix set out in the yard. Can pull a bowed wall back over several seasons. Needs yard access.
| Modelled US range | $650–$1,400 per anchor |
|---|---|
| Disruption | Inside and outside, 2–4 days. |
| Expected life | Permanent. |
Push pier / helical pier underpinning
Steel piers driven to load-bearing strata under the footing, then the structure is lifted or stabilised on them. This is the real structural repair, and the one that gets to five figures fast — a typical job is 8–16 piers.
| Modelled US range | $1,500–$3,200 per pier |
|---|---|
| Disruption | Excavation at each pier, 3–10 days. |
| Expected life | Permanent, usually with a transferable warranty. |
Polyurethane / epoxy crack injection
Fills a single non-structural crack in a poured wall. Correct fix for a leaking hairline crack. Wrong fix if the crack is moving — it will simply crack again beside the repair.
| Modelled US range | $400–$950 per crack |
|---|---|
| Disruption | Inside, hours. |
| Expected life | Long, provided the wall is not still moving. |
Why we will not give you one number
Because the honest spread is wide, and the sites that quote a single figure are either guessing or being paid to anchor you. The same interior drain in the same soil differs by a factor of two between a firm with a national franchise fee and a two-truck local outfit. What a range is good for: recognising a quote that sits outside it, in either direction. A bid at half the low end usually means a coating being sold as a drainage system.
Price book 2026.08, updated 2026-08-11. Built from published editorial ranges: Angi · HomeAdvisor · This Old House · Bob Vila · Forbes Home. Regional factor is a labour-cost index, not a contractor price list.
Cost questions
Why is exterior waterproofing three times the price of interior drainage?
Because you are paying for excavation, not for waterproofing. Digging 8 feet down around a house, keeping the trench safe, and putting the yard back is most of the cost. The membrane itself is cheap.
Is the “free inspection” really free?
It costs no money. It is a sales visit by someone whose company sells one family of products, and the diagnosis tends to match the catalogue. That is not fraud, it is incentive. It is also why an independent structural engineer’s letter, at $400–$1,150, is the cheapest thing you can buy before a five-figure decision.
Can I do any of this myself?
Grading, downspout extensions and window well drains — yes, and they solve more wet basements than the industry likes to admit. Breaking a slab, excavating against a foundation wall, or anything involving a bowing wall — no. A retaining failure while you are standing in the trench is not a recoverable mistake.
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