Structure
How should you read a mundic comment on a concrete-block house?
Mundic is a concrete problem associated with parts of the south west of England. A home survey can say the walls look like concrete block and whether it saw deterioration. It does not drill cores or give a mundic class. Cornwall Council describes that test as a separate examination. RICS publishes guidance for surveyors who meet it.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless a source says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
Why is a visual home survey not a mundic class?
A home survey looks at what it can see. Crumbling block, cracks or a damp concrete face can be written down. None of that is the classification RICS describes for mundic samples. Cornwall Council says the test takes cores and examines the concrete. A surveyor who did not drill has not done that test.
Do not turn a sentence such as concrete block, possible mundic into a pass or a fail. Ask whether a separate test has been recommended, and ask the solicitor whether any old report is actually in the pack. An old letter is not this week's inspection.
Where does the RICS mundic guidance apply?
The RICS guidance note on the mundic problem is written for surveyors likely to meet it in the south west of England. It discusses routine testing in Cornwall and in a defined area of Devon, and it discusses older concrete rather than every house. A house outside that discussion can still be concrete. The guidance does not clear it, and it does not condemn it.
The same note is not a mortgage offer. Lenders set their own criteria. This page does not invent them. A valuation that says nothing about concrete has not classified the block, and a condition note that mentions concrete has not valued the house.
What should you ask if the walls are concrete in Cornwall or Devon?
Ask the survey firm whether this instruction includes core sampling. A Level 2 or Level 3, as RICS describes those products, is still a home survey. It is not automatically the mundic procedure. If they recommend a test, that test is a further instruction with its own scope.
Ask the solicitor for any existing classification and for the date on it. Cornwall Council describes classes from the examination of cores. A seller's memory of a class, with no report, is not the document. Read the report you are given rather than the word the agent used.
Common questions
The seller has a letter saying Class A. Has this survey repeated that result?
Only if this inspection took cores and a laboratory examined them. A normal home survey does not. The letter is a separate document. Ask how old it is and which walls it sampled. Do not treat it as the condition rating in today's report.
Cores were taken from the garage only. Is the house classified?
The result describes the cores that were taken. Cornwall Council's description of the test includes walls and, where accessible, other concrete. A garage core does not speak for a house wall that was not sampled. Read what the laboratory report actually lists.
The front is brick and the side wall is concrete block. Which face matters?
The concrete, if that is what may contain the aggregate the guidance is about. Brick on the front does not classify the block on the side. The survey should say what it could see of each. It still has not tested either.
A concrete house in Cornwall has no crack. Is a test unnecessary?
A quiet wall is what the survey saw. RICS discusses when routine testing is considered, and it also discusses signs of deterioration. Absence of a crack in one visit is not the laboratory class. Ask the firm whether they are recommending a test, and do not invent a rule they did not write.
The house is concrete but outside the area the guidance maps. Can you ignore the block?
No. The guidance discusses where routine testing is focused. It does not say concrete elsewhere is of no interest if the surveyor sees deterioration. The home survey still only records what it saw. It does not issue a class either way.
The report says further investigation of the concrete. What appointment is that?
Not one the survey has already made. It means someone who samples and classifies concrete, which is the examination Cornwall Council describes, not another look from the pavement. Agree the scope before you treat the house as tested.
The lender has asked for a mundic test and the survey did not do one. Did the survey fail?
No. The lender's criterion is the lender's. The home survey describes condition within its scope. If that scope did not include cores, the test is still to be commissioned. Do not read the survey as having refused the lender.
The chimney breast looks like concrete and the walls are brick. What was not tested?
Both, unless cores were taken from each. A concrete breast in a brick house can be a different material from the walls. The survey can note what it looks like. A class, if you need one, has to name the samples.
Sources
Key facts
- What a survey can say
- That the walls appear to be concrete, and what deterioration it could see. Not a class.
- The test
- Cornwall Council describes core samples and a staged examination. The council does not itself provide the test.
- Where routine testing is discussed
- RICS guidance is for the south west, focused on Cornwall and a defined part of Devon, mainly older concrete. It is not a result for this house.
- A class in the pack
- A letter saying Class A, B or C is a laboratory document. The home survey has not repeated that test unless it says it took cores, which a normal inspection does not.