Subsidence and Underpinning Costs UK: Cracks, Causes and Prices
Underpinning costs £6,000-£21,000 and crack repair £2,000 upwards. After a record year for subsidence claims, here are the causes, the costs, and how to check an underpinning quote.
Subsidence is one of the most stressful things a homeowner can face, and after a run of hot, dry summers, UK insurers have reported record numbers of claims. That makes it a prime moment for panic decisions and overcharging. The single most important thing to know is that you should rarely commission underpinning yourself before involving your insurer. Here are the costs, the causes, and how to check a quote.
First: talk to your insurer
If you suspect subsidence, contact your buildings insurer before commissioning any structural work. Most policies cover subsidence (subject to a high excess), and the insurer will normally appoint their own structural engineer to diagnose the cause and manage the repair. If you arrange and pay for underpinning yourself first, you can prejudice or invalidate the claim. The cost figures below are mainly relevant if you are uninsured for it, or for the parts a claim does not cover.
Quick cost summary
| Work | Typical cost |
|---|---|
| Structural engineer's investigation and report | £500-£1,500 |
| Crack repair and redecoration (minor movement) | £2,000-£6,000 |
| Resin injection underpinning (suitable ground) | £6,000-£12,000 |
| Traditional mass-concrete underpinning | £12,000-£21,000+ |
| Severe / piled underpinning | £20,000-£50,000+ |
Prices based on UK trade averages and MyBuildAlly quote analysis, mid-2026. The method, the length of wall, and access drive the figure.
Is it actually subsidence?
Not every crack is subsidence. Most homes move slightly with the seasons, and hairline cracks are usually harmless. Genuine subsidence tends to show as diagonal cracks, wider at the top, around openings and where an extension meets the original house. Because the treatments are expensive, diagnosis by a structural engineer matters before anyone reaches for underpinning. Our guide to checking foundation work and minimum foundation depths covers the groundwork side.
Fix the cause, not just the symptom
Underpinning the wall without addressing why the ground moved is treating the symptom. The two most common causes are clay soil shrinking near foundations (often worsened by a thirsty tree) and a leaking drain washing soil away. A proper repair identifies and fixes the cause: managing or removing a tree, or repairing the drain. A quote that goes straight to underpinning with no investigation of the cause is incomplete, and the movement can simply return.
The methods, briefly
- Resin injection: structural resin injected into the ground to stabilise and lift. Quicker, less disruptive, cheaper, suited to certain soils.
- Mass-concrete underpinning: digging out and pouring concrete beneath the existing foundation in sections. The traditional method, more disruptive and costly.
- Piled underpinning: piles driven to firmer ground, used for deeper or more serious cases. The most expensive.
The right method depends on the ground and the cause, which is the engineer's call, not the contractor's.
What a fair underpinning quote includes
- A structural engineer's report identifying the cause
- The method and the length of wall treated
- Fixing the cause (tree management, drain repair) where relevant
- Building Control involvement (underpinning is notifiable work)
- Making good: re-rendering, crack repair, and redecoration
- A guarantee, and how it interacts with future insurance
Check your quote
Subsidence work is high-value, stressful, and easy to over-treat, which is the worst combination for getting a fair price. If you are dealing with this outside an insurance claim, upload your quote and we check the method, the cause, and the price against the benchmarks above, and flag it when the investigation or the cause-fix is missing. It takes under a minute.
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