Subsidence, settlement and heave
The crack is wider at the bottom than the top. Why is that pattern a clue and still not a finished diagnosis of heave?
The pattern is a clue, not a finished diagnosis of heave. The crack is wider at the bottom than the top, a shape often linked with upward movement rather than a crack that opens more toward the top. Swelling ground, a removed tree or a change in soil moisture can produce that pattern, and so can other causes that only look similar. The survey recorded the taper. It did not monitor the crack, did not test the soil, and has not decided that heave is what happened here.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Diagnosis of heave needs more than a tapered line in plaster. It needs a history of the ground, sometimes levels, and often time, so that opening and closing can be told apart from a crack that simply formed once. This visit had the shape on one day. It did not take a soil sample and did not set tell-tales of its own. The clue is worth keeping, because it stops anyone casually calling the crack ordinary settlement. It is not a completed cause.
Tell a lender or insurer, if you must describe it, that the crack is wider at the bottom and that heave has not been diagnosed. If someone needs a cause, that is a specialist monitoring or ground instruction, kept separate from this report. Do not let the pattern be written up as proved heave, and do not let it be ignored. The survey's care is in stopping at the clue.
What should you ask your surveyor?
- Is the wider-at-the-bottom pattern being reported as proved heave?
- Was the soil tested or the crack monitored over time?
- Has any other cause been ruled out on this visit?
What are the typical next steps?
- Call the pattern a clue, not a heave diagnosis.
- Keep any ground or monitoring instruction separate from this report.
- Do not tell a lender that heave has been proved.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does a crack wider at the top mean the opposite movement?
It can be a different clue, often discussed with downward movement, but it is still only a clue. This crack is the other way, wider at the bottom, and even that has not been diagnosed as heave. Shape points. It does not finish the cause. The survey did not test the ground in either case.
Can old repairs along the crack close the diagnosis?
No. Old filler shows someone once covered the line. It does not show whether the crack is heave, whether it has moved since, or whether the repair was structural. The survey recorded the present taper and stopped. A filled crack can reopen. The diagnosis remains unfinished.