Non-standard construction
The survey suspects mundic-type concrete in a Cornish block wall and does not give it a class. Why must you not invent the class from this page?
The survey's suspicion of mundic-type concrete in this Cornish block wall is not a class, and you must not invent one. The report suspected a concrete type. It did not classify it. No class letter and no figure for the affected concrete belong on this page, because none was given. A suspicion is a reason to investigate with a proper test, if you need classification. It is not itself the result of that test, and the survey has not supplied the missing label.
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?
Mundic is a name for a concrete problem associated with some Cornish blocks. Naming the suspicion tells you the surveyor was not prepared to call the wall an ordinary mix. It does not tell you which outcome a laboratory or a specialist scheme would reach. Copying a class from another house, or from memory of a letter scale, would be fiction.
Ask what was seen: the blocks, the aggregate, or only a reason to doubt. Then decide with your solicitor whether a classification test is required before you commit. Until that test exists, the honest sentence is the one the survey already used. Do not improve it. Do not tell a lender a class the report refused to give.
What should you ask your surveyor?
- What did you see that led you to suspect mundic-type concrete?
- Have you given the concrete any class, or have you stopped at a suspicion?
- What further test, if any, would you expect before a class is stated?
What are the typical next steps?
- Do not invent a class or a figure for this concrete.
- Keep the wording as a suspicion, which is what the survey actually said.
- Ask whether a separate classification test is needed before you exchange.
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 blocks look poor, can you assume the worst class?
No. Poor appearance is not a class. The survey suspected a type and did not classify it, so no letter and no figure should be added.
Does a Cornish address automatically mean mundic of a known class?
No. The address is not a test result. This wall was suspected, not classified, and another house's result does not transfer to this one.