Subsidence · underpinning history
The question isn't the crack. It's whether the house is still moving — and there's a sale either way.
Finding your kitchen has shifted is genuinely frightening, and the word "subsidence" frightens buyers just as much. But moving and fixed are two different problems with two different prices — and this summer's heatwaves mean you're far from alone.
What the surveyor sees — and what actually matters
Tap each number. One structural engineer's line to a worried London homeowner: "You and 20,000 other people in southeast London."
1The crack — moving, or long fixed?
Stepped cracking near a window or door is the classic sign, and finding it is frightening — one homeowner called the moment their kitchen shifted "genuinely scary". But a surveyor's real question isn't the crack, it's the movement: active subsidence and historic, stabilised subsidence are priced like different planets. Everything on this page hangs on which one yours is — and monitoring, not guesswork, is how that gets answered.
2The ground it stands on
Most UK subsidence is shrink-swell clay: the soil dries in hot summers, shrinks, and the foundations follow it down — with thirsty trees and leaking drains making it worse street by street. That's why claims surged through 2026's heatwaves — one insurer took 180 in a single day, and payouts hit a record £297 million over four years. If you're on the London and South East clay belt, you have plenty of company: "you and 20,000 other people in southeast London."
3Underpinning — and the paper that matters more
Underpinning averages £12,500 and runs £20,000 to £100,000+ at the severe end, over three to six weeks. But here's what agents actually see: "buyers hear 'underpinned' and walk" — unless the paperwork holds. A certificate of structural adequacy and the complete claim file turn "underpinned" from a scare word into an engineering record. Documented and stabilised can sell close to normally; undocumented can't.
4The insurance history that follows the house
After a subsidence claim, renewals jump or cover is refused — and the claims history stays with the property, not with you. Buyers' lenders want continuity of buildings insurance, so the insurance question can block a sale even after the engineering is fixed. The hardest case of all is active, unstabilised movement with no insurer on cover: without buildings insurance there's no lender and almost no market. If that's where you are, call us and we'll be straight about what's possible.
Sources: Checkatrade, subsidence repair costs · Insurance Journal, 24 Aug 2026. General information, not structural or legal advice — a chartered structural engineer answers the moving-or-fixed question, not a webpage. Last reviewed August 2026.
Your three honest routes
Which one is right depends almost entirely on whether the movement has stopped.
Stabilise, certify, sell normally
If the movement is active, this is the route to full value: engineer's investigation, repair or underpinning through your insurer where you can, then the certificate of structural adequacy and the complete claim file handed to the buyer. Historic and documented can sell with surprisingly little discount.
£12,500 on average and up to £100,000+ severe, three to six weeks of works — after months of monitoring first, because engineers won't certify what they haven't watched. This route is measured in seasons, not weeks.
Sell disclosed on the open market
Houses with subsidence history do sell — with full disclosure, the claim file on the table, and a price around 20–25% under for ongoing movement. The agent's honest version: "price it 20% under and hope." Auctions take structural-issue stock and can work for the right house.
Mortgage buyers thin out fast once the survey lands; insurance continuity questions can kill a sale late; and every renegotiation starts from the scariest line in the report.
Sell to us as it stands
We buy without a lender, so there's no mortgage valuation to fail and no insurance-continuity condition to trip. Tell us everything — the monitoring, the claim, the certificate or the lack of one — and the offer is made knowing it, so it can't drop when our survey reads the same file. You pick the completion date.
The price is below market value — 65–82% depending on the date you choose, judged against what the house is realistically worth with its history, and shown before you give us anything. Active, uninsured movement is the one case we may not be able to price on a webpage — we'll tell you on the phone, straight.
The certain route: no lender to spook, a figure made after the bad news, and a date in writing with £500 a day on us if we miss it.
"Buyers hear 'underpinned' and walk." Why we don't.
A mortgage buyer is risking their deposit and their lender's money on a house they'll own for decades — so the word alone is enough to send them elsewhere, whatever the engineering says. We price on the file, not the word: the monitoring record, the repair scope, the certificate, the claims history. A properly underpinned house on stable ground is, structurally, often the strongest house on its street — and an honestly documented one is a property we can price with confidence, which is what lets us commit to a date.
Disclose everything, including what you're unsure of. The property form asks about movement and claims directly, a knowingly wrong answer can follow you after completion, and — as with everything you tell us up front — disclosed facts are locked by our price promise: they cannot be used to move the figure later.
The questions subsidence sellers ask
The crack appeared this summer. Is it definitely subsidence?
My house was underpinned in the 1990s. Is that still a problem?
My insurer is handling it now. Should I wait for the works?
The tree next door caused it. Can I make them pay?
Get a figure made after the bad news
There's no obligation and nothing to sign. We'll give you a figure in writing, with our reasoning, and you can take it to anyone you like before you decide.
Or call us: 0191 249 3969 · 8am–8pm, seven days