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Survey finding

Heave on your survey: what it means and what to do

Serious

Heave is the often-misunderstood opposite of subsidence: the ground pushes upward, not downward. This page covers what causes heave, why the structural response is rarely a single recipe, and how mortgage and insurance markets treat heave properties.

Last updated: 6 May 2026. Editorially reviewed: 20 May 2026.

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Finding

Heave (ground movement)

Serious

What this usually means

Heave is the opposite of subsidence, ground swells upward, lifting foundations and producing characteristic horizontal cracks. The most common cause is removal of a tree near a clay-soil property: the tree's roots had been taking moisture out of the clay, and once removed the clay re-wets and expands. Other causes include leaking water mains saturating clay, frost heave on shallow foundations, and chemical attack on concrete (sulphate heave).

Why it matters

Heave is structurally serious because the upward force on foundations is hard to resist with conventional repair. Conventional underpinning is rarely the first remedy for active heave, solutions include void-forming foundations on new extensions, chemical soil stabilisation, partial excavation and replacement, and (most often) waiting for the ground to re-equilibrate over 2–5 years while monitoring movement before any structural repair. The right answer is the structural engineer's, not a generic recipe. Insurance and mortgage implications follow accordingly.

Ask your surveyor

  • Check:What is the most likely cause, tree removal, leaking main, frost heave, sulphate attack?
  • Check:Is the movement active or historic, and what monitoring would you recommend?

Ask the seller

  • Check:Has any tree been removed near the property in the last 10 years?
  • Check:Has there been any insurance claim for heave or subsidence?

Next steps

  • Get two written quotes from local trades before negotiating with the seller.
  • Speak to your mortgage broker before exchanging if the finding affects mortgageability.

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What you need to know

Severity

4/ 5

Serious. Lender and insurer involvement likely; structural or specialist remediation.

Typical cost to fix

Structural engineer's report £500–£1,200. Level monitoring £300–£600 per visit. Repair cost varies hugely: cosmetic re-pointing £1,500–£3,000; structural repair £8,000–£25,000; void-forming foundations on new extensions £15,000+. Where a heave-related insurance claim is active, the insurer often funds repairs.

Mortgage impact

Active heave generally produces a mortgage retention until movement is shown to have stabilised, with structural engineer's sign-off. Lenders treat heave more cautiously than historic subsidence because remediation is harder. Some specialist lenders consider heave properties at higher rates.

Insurance impact

Heave is covered under standard UK buildings insurance for properties with no prior claim. Once a claim has been made, future placement is constrained, most insurers will continue cover with a higher excess (typically £1,000+ for subsidence/heave) but will not accept new business on a property with an active claim. Disclosure of any prior heave claim is required.

When to pull out

Pull out if heave is active and unstabilised, the cause has not been identified, and the seller refuses to wait for monitoring data. Heave on a property where a tree has recently been removed is a wait-and-watch situation, not a refurbishment one.

When to renegotiate, and by how much

If heave is historic and stable with engineer's sign-off, treat as standard. If active, negotiate on the basis of the engineer's full remediation estimate plus monitoring costs plus 20% buffer; settled outcomes commonly 10–20% off price.

Thinking of pulling out or renegotiating? What to do after a bad survey

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Subsidence monitoring , often sits near heave (ground movement) on a survey and is the next thing to check.

Editorial review

Editorial owner: BiteRight Ltd, operator of MyPropertyScan. We review buyer guides against UK public property datasets, RICS survey wording, lender requirements, and common buyer questions.

Pages are updated when source coverage, property-risk guidance, survey cost assumptions, or product checks materially change. Methodology and dataset limitations are explained on the MyPropertyScan methodology page.

Sources used

We use UK public and specialist sources where they are available. Public datasets can be incomplete, delayed, or missing for some addresses. Treat them as a starting point, not as a replacement for professional advice.

Source standard: preference goes to official government datasets, statutory bodies, professional standards, and primary dataset publishers. We cite the source family on the page and explain coverage limits rather than filling gaps with unsupported estimates.

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