Roofs and flat roofs
What should you ask if a gap has opened between an upstairs wall and the ceiling?
Ask whether the surveyor thinks the roof structure is moving, and what else they saw at the eaves. A gap at the ceiling line can be roof spread, a shrunk timber, or plaster that has let go. It is not automatically subsidence. A home survey sees the crack. It may not see the rafter feet if the loft was not entered.
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?
The useful outside clues are a wall that leans out at the top, a gap under the eaves soffit, and a ridge that has dropped. Inside, doors on the top floor that no longer fit can match. RICS describes the inspection as visual and limited by access. Approved Document A is about structural work in England when building regulations apply. It does not label this crack.
Plaster cracks alone are cheap to fill and useless as evidence if you fill them before anyone looks. There is no RICS price for a structural tie. If the survey could not get into the loft, say that in the quote request. Do not buy a full re-roof because a cornice has opened.
What should you ask your surveyor?
- Could you see the rafter feet and the wall plate?
- Is the gap only in plaster, or is the wall itself out of line?
- Are you distinguishing this from foundation movement?
What are the typical next steps?
- Do not fill the gap before a second opinion if the survey is worried about the roof.
- Ask for loft access if it was refused.
- Tell a roofer or an engineer which clue was structural and which was plaster.
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
Can ceiling cracks from a loft conversion look similar?
Yes. New openings and cut timbers are a different cause. Ask whether the loft was altered.
Does a hairline at every ceiling mean spread?
No. Hairline plaster cracks are common. The survey should say if that is all they are.