Subsidence, settlement and heave
What should you ask if a wall bows but there is no fresh crack?
Ask how the bow was judged and whether it is progressive. A bow is a shape. A crack is a break. You can have either without the other. A home survey sees the line of the wall. It does not monitor it, and it does not prove subsidence, wall-tie failure or roof spread. Those have different patterns. The Association of British Insurers describes subsidence as a downward movement of the ground. A bow is not automatically that.
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?
Ties often crack bed joints in a repeating pattern. Roof spread often pushes the top of a wall out. A retaining wall bows because it holds ground. The surveyor should say which storey they mean. If they could not decide, further investigation is a scope, not a rating you can price from a photo.
An engineer measures and, if needed, monitors. There is no RICS price for that. Do not hack off render or demolish the wall before exchange because it “looks out”. If the rating is 3, get a written view before legal commitment, which is what the Level 3 description asks for when repairs or investigation are urgent.
What should you ask your surveyor?
- Where is the bow: the top, the middle, or a retaining wall?
- Are there cracks, or only a curve?
- What investigation would tell the causes apart?
What are the typical next steps?
- Photograph along the wall so the curve is visible, not only a close-up.
- Do not start tying or rebuilding until someone has said which mechanism it is.
- Keep insurance talk about subsidence separate until a cause exists. ABI advice is not a claim you have already made.
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
Is a bulge in render a bow in the wall?
It might be the coat leaving the wall. Tapping hollow render is not a line survey of the masonry. Say which you could see.
Does a bow mean the house is unsafe to enter?
Only if the surveyor says so. Many bows are old and stable. Do not evacuate from a sentence that says “distorted”. Ask.