Subsidence, settlement and heave
What can a survey say if only one corner of the house sits on a concrete plinth?
It can describe the plinth it can see: the extent along each wall, the height above ground, and any crack that starts or stops at it. It cannot certify that the corner was underpinned to a design, that the concrete is deep enough, or that movement has stopped. One visit does not monitor the building, and the survey does not test the soil.
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?
Partial underpinning is sometimes used at a single corner that has dropped, leaving the rest of the house on its original footing. A concrete plinth, a change of brick, or a vertical joint in the base of the wall can be the only clue from outside. Those clues are not the drawings, the depth, or the ground conditions. The Association of British Insurers describes subsidence as downward movement of the ground. A plinth does not tell you whether that movement has finished, or whether the untreated walls are now carrying a different load.
Do not describe the corner as “guaranteed” because concrete is visible. The surveyor has not excavated beside the plinth and has not seen the bearing stratum. Ask them to limit the sentence to what was visible. If you need someone to say whether the partial work is adequate, that is a structural engineer with the papers, not a second reading of the same plinth. The neighbour’s wall, if the corner is on a boundary, is a separate question for your solicitor. The survey does not decide it.
What should you ask your surveyor?
- How much of the base is concrete, and how much is the original footing?
- Does any crack stop at the plinth, cross it, or start from it?
- Are you certifying the underpinning, or only describing the plinth?
What are the typical next steps?
- Ask the seller for any drawings, calculations or completion letters, and do not invent them if they are missing.
- Describe the plinth to your solicitor as visible concrete, not as a certified repair.
- If the lender asks whether the house was underpinned, send the surveyor’s wording and the papers. Do not upgrade either.
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 plinth on one wall the same as underpinning the whole house?
No. One corner is one corner. The other walls may still be on the original base. The survey should not be read as covering them.
Can the surveyor measure how deep the concrete goes?
Not on a normal inspection. Depth is underground. What you have is the face above the soil.