Subsidence, settlement and heave
Concrete nibs show at the base of the flank wall and there is no underpinning drawing in the pack. What work might that concrete be, and what has not been verified?
The concrete might be underpinning, a local thickening, or some other base detail, and none of that has been verified. Concrete nibs show at the base of the flank wall, and there is no underpinning drawing in the pack. The survey can describe the concrete it could see at ground level. It cannot say how deep it goes, whether it was designed, or whether it is the edge of a proper underpin. Seeing a nib is not the same as reading a drawing. The inspection has not confirmed what the concrete is.
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?
Underpinning is sometimes visible as a concrete projection at the foot of a wall, but so is a haunch, a thickened path edge, or a past patch. The shape at the surface does not identify the work. With no drawing, there is no depth, no width, and no designer’s name to check against the nib. The survey did not excavate beside the flank wall and did not test the concrete. The Association of British Insurers describes subsidence repair as an insurer’s process when a claim is involved.
Ask the solicitor for any underpinning drawing, guarantee, or building-control paper, and if none comes, treat the nib as unidentified concrete. A structural engineer can inspect it if the flank wall also shows movement. Do not tell a lender the house has been underpinned merely because concrete shows at the base. The survey saw nibs. It did not verify the work.
What should you ask your surveyor?
- What did the concrete nibs look like, and on which wall?
- Was any underpinning drawing in the pack you were given?
- Did you excavate or test the concrete, or only see it at the surface?
What are the typical next steps?
- Call the nibs visible concrete, not verified underpinning.
- Ask the solicitor for any drawing, guarantee or approval.
- Refer the flank wall to an engineer if movement is also recorded.
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
If the nibs are neat, were they done properly?
Neat concrete is a tidy edge, not a verified underpin. The survey saw nibs at the base of the flank wall and had no drawing. It did not check depth or design. A straight finish can belong to a path haunch as easily as to structural work. Appearance has not identified the concrete.
Does the lack of a drawing mean the work was informal?
No. A missing drawing means the pack did not verify the nibs. The work might have been designed and the paper lost, or it might never have been designed. The survey cannot choose between those. It recorded concrete at the base. It did not confirm underpinning.