Non-standard construction
The survey says clinker block and a forum has told you that means mundic. Why should those two words not be glued together without a test?
Do not glue clinker block and mundic together without a test. The survey's words are clinker block, which is a description of the wall material the surveyor believes they saw. A forum saying that means mundic has skipped the test that would be needed to say so. The home survey has not carried out a mundic screen, and a nickname on the internet is not that screen. Clinker block can be discussed as non-standard construction. Mundic is a separate conclusion about concrete, and it is not established by renaming the surveyor's phrase.
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?
Surveyors use block names to tell you what the wall appeared to be, so that a lender or a buyer is not misled into thinking it is ordinary brick. That naming is already useful, and it is already limited. It does not sample the aggregate and it does not grade deterioration. Forums collapse names. If a mundic screen is appropriate, it will say what it found in a document of its own. Until then the wall is what the survey called it: clinker block, untested for mundic.
Ask the surveyor to confirm the phrase they actually used, and ask the solicitor or lender whether this construction triggers a request for screening. If it does, commission the screen rather than adopting the forum. Do not amend the survey in your own notes to say mundic confirmed. Report the forum as an unverified comment if you mention it at all. The inspection decided a descriptive label. It did not decide a screening result.
What should you ask your surveyor?
- What construction name did you use, and did you stop short of mundic?
- Has any screening test been done, or only a visual description?
- Which forum claim should not be written into your wording?
What are the typical next steps?
- Keep the survey's phrase as clinker block.
- Do not rewrite that phrase as mundic without a test.
- Ask whether a lender wants a separate screen.
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 house is outside Cornwall, can the forum still be right?
A forum is still not a test, wherever the house stands. The survey said clinker block. It did not carry out a mundic screen, and geography does not glue the two words together without a screening test. Wait for a real screen.
Does crumbling mortar on its own prove mundic?
No. Crumbling mortar is a condition the survey can describe. It is not a screening result, and it does not convert a clinker-block note into a mundic finding or a screen. Mortar wear is a surface comment, not a mundic screen.