Subsidence, settlement and heave
Why can one survey visit not tell you whether a crack is still moving?
Because movement is a change over time, and the surveyor sees the crack once. They can record width, direction and whether it looks fresh. They cannot draw a trend from a single afternoon. The Association of British Insurers’ account of subsidence is about the ground moving. A description of a crack is not a monitoring exercise.
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?
Crack monitoring uses fixed points read more than once. Tell-tales already on the wall are evidence only if someone has the earlier readings. A hairline that looks old and a crack with sharp clean edges are clues, not dates. The home survey should say it is one visit. Buyers who want a yes-or-no before exchange are asking for a second activity, not a rewrite of the first report.
An engineer may say the pattern is historic, or that it needs measuring, or that a drain should be checked first. Those are different costs. None is a national tariff. Do not delay exchange for monitoring you have not agreed, and do not pretend the survey already contains the months of readings it does not.
What should you ask your surveyor?
- Are you describing one visit, or have you seen this crack before?
- What would need to be measured to know if it is live?
- Which other causes, such as a drain or a lintel, sit beside this crack?
What are the typical next steps?
- Do not invent a trend from two photographs taken the same day.
- If monitoring is recommended, ask how long and who reads it before you commit.
- Keep the seller’s old photos, if any, with dates.
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 wider crack always mean it is still moving?
Width is not a clock. A wide crack can be old. A hairline can be new. The survey should not pretend otherwise.
Can you monitor a house you do not yet own?
Only with the seller’s agreement. Studs on their wall are their consent, not a right in the survey.