Subsidence, settlement and heave
A concrete cap in the garden is said by the seller to be an old shaft. Can the survey confirm the cap is adequate?
No. The survey cannot confirm that the concrete cap in the garden is adequate. The seller's say-so that it covers an old shaft is a statement, not a test of the cap. The inspection can record a concrete slab, its visible condition and where it sits. It cannot see the shaft beneath, the quality of any filling, or whether the cap was designed for that hole. A Coal Authority search is a separate product from the home survey. Adequacy of a shaft cap is not something this visit has certified.
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?
Concrete in a lawn can be a path, a base, or, as the seller claims, a cap. Looking at the top tells you about cracks, edges and whether the surface is proud of the grass. It does not tell you the diameter of a shaft, the depth, or what the cap is tied into. The survey should keep the seller's words labelled as the seller's words. Confirming adequacy would need the mining records and someone competent to judge a shaft cap, which is outside a home inspection.
Pass the seller's claim to the solicitor with the request that the Coal Authority search, and any shaft-specific information, be obtained and read against the garden. Do not tell a buyer, or yourself, that the survey has passed the cap because the concrete looked thick. Thickness was not measured through the slab, and adequacy was not decided. If a record shows a shaft, follow that record rather than the appearance of the cap on the day.
What should you ask your surveyor?
- Did you record the concrete as seen, and the shaft claim as the seller's?
- Have you avoided saying the cap is adequate?
- What sits outside this inspection if a shaft is later confirmed on a search?
What are the typical next steps?
- Treat the seller's shaft claim as unverified.
- Do not read the concrete cap as certified adequate.
- Ask the solicitor for the mining search and any shaft record.
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 cap is cracked, has the survey then condemned the shaft?
A crack is damage to the concrete you could see. It is not a measurement of a shaft and not a verdict that a cap has failed in an engineering sense. The survey still has not confirmed what is underneath.
Can the surveyor lift the cap to check the hole?
No. Lifting a claimed shaft cap is not part of a home survey and was not done. The report records the surface. It does not open the ground to prove or disprove the seller or to pass the cap. Adequacy is untouched.