Who pays for underpinning, me or my insurer?

Underpinning can be an insured repair or a cost you choose to take on, and the difference matters for who foots the bill. The sections below set out when each applies and the cases where another party may be liable.

When your insurer pays

Buildings insurance covers underpinning where it is the least-cost lasting repair for damage caused by an insured peril — subsidence, heave or landslip. In that case the insurer funds the investigation, the agreed works and the reinstatement, and you contribute only the subsidence excess. The key conditions are that the damage is sudden and recent rather than long-standing, that you disclosed any known history when taking out the policy, and that you let the insurer lead rather than commissioning your own underpinning first.

• Covered: underpinning specified by the insurer's engineer to fix insured subsidence.
• Not covered: underpinning you choose for an extension, basement or to add value.
• Disputed: long-term settlement, where the insurer may argue the damage is not sudden subsidence.

When you pay yourself

You meet the cost where underpinning is a voluntary structural change or falls outside the policy. Common examples are underpinning to allow a loft conversion or a deeper basement, to support a new extension, or to correct the gradual bedding-in of a recently built home — none of which is sudden insured damage. You also pay where a claim is validly declined, for instance because the damage pre-dates the policy or arose from poor maintenance. In these cases underpinning costs are significant, so it is worth getting a structural engineer's view on whether a less invasive solution would work.

Where you are funding the work yourself, you also take on the role the insurer would otherwise play: appointing a structural engineer to design the scheme, choosing a contractor, and arranging building control sign-off, since underpinning is notifiable structural work under the Building Regulations. The engineer should still issue confirmation that the works are structurally adequate at completion. Keeping that documentation matters just as much on a self-funded job as on an insured one, because a future buyer, surveyor and insurer will want evidence that the underpinning was properly designed and signed off.

When someone else may be liable

Several situations move liability to a third party, though your own insurer usually still leads the repair and then seeks to recover its costs:

• A neighbour's tree drawing moisture from shrinkable clay can make that neighbour, or their insurer, liable for the damage it causes.
• A new build with structural defects may be covered by the developer's warranty, such as NHBC Buildmark, during its term.
• A collapsed or leaking shared drain or sewer may be the responsibility of the water company, which can affect who ultimately pays for the resulting repairs.

In each case, report the matter to your buildings insurer first; the insurer's loss adjuster handles any recovery from the responsible party so you are not left to pursue it alone. This recovery process, sometimes called subrogation, happens in the background — the insurer pays for your repair and then pursues the third party for the cost, so you are not waiting on a neighbour's cooperation before your own claim proceeds.

What 'insurer pays' means in practice

When the insurer pays, it rarely hands you a lump sum to spend as you choose. On a subsidence claim the insurer typically manages and funds the works directly through its own approved engineer and contractors, applying your excess. That keeps the repair within the scope the engineer specified and allows the Certificate of Structural Adequacy to be issued at the end. The benefit to you is that the insurer carries the cost and the project management; the trade-off is that you have less direct control over who carries out the work and exactly what is done.

Because the insurer funds the least-cost lasting repair, the method is the engineer's decision, not yours. If monitoring shows that removing a tree and repairing a drain stabilises the ground, that is what will be funded, even if you would have preferred underpinning for reassurance. Equally, where the engineer concludes underpinning is genuinely needed, the insurer pays for it. The principle is consistent: the policy restores the building to a sound condition, using the repair the evidence supports, rather than funding the most extensive option available.

This shared-control arrangement also explains why your own contribution stays limited to the excess. You are not project-managing a builder and settling invoices; the insurer is, and it carries the financial risk if costs run over the original estimate. The flip side is that if you want a say in the contractor or the finish, you need to raise it early with the loss adjuster, because once the insurer's approved scheme is underway the scope is set by what the engineer specified rather than by preference.

One further point on liability is worth holding onto: who ultimately bears the cost and who manages the repair are two different questions. Even where a third party — a neighbour, a developer's warranty provider or a water company — is ultimately responsible, your own buildings insurer normally still leads the repair and recovers its outlay afterwards. That arrangement protects you from being left to fund or chase the work yourself while a liability argument plays out. The practical rule is the same in almost every case: report the damage to your own insurer first, let its engineer establish the cause and the method, and let the insurer handle any recovery, rather than trying to identify and pursue the responsible party before your repair can begin.

Frequently asked questions

Sources & further reading

• Association of British Insurers — subsidence guidance
• Citizens Advice — problems with neighbours (trees and boundaries)

Figures on this page are typical UK ranges drawn from published sources and depend on your specific property. They are guidance, not a quotation.