A mundic blockA type of concrete block that may be used in the constructio... More property is a building constructed using concrete made with local mine or quarry waste, mainly found in Cornwall, West Devon, and parts of South Devon. Some of these materials can deteriorate over time, so most lenders require a mundic test before agreeing a mortgage. Whether you can get a mortgage depends on the test result, which grades the concrete from sound to unsound.
This guide explains what mundic block means, how mundic testing works, what the results mean, and how lenders decide whether to lend on a mundic property.
What does mundic block actually mean?
Mundic is a Cornish term for mine waste. Between roughly the 1900s and the 1950s, concrete blocks and mass concrete in the South West were sometimes made using waste material from local mines and quarries. Over decades, certain aggregates in this concrete can break down, potentially affecting the structural integrity of the building. Because the risk is specific to the region and the era, lenders treat these properties with caution and rely on a specialist test rather than a standard valuation alone.
How does mundic testing work?
A mundic test is carried out by a qualified surveyor who takes core samples from the concrete and has them analysed in a laboratory. The results are graded, commonly as Class A for sound material suitable for mortgage purposes, Class B for uncertain material that may need further testing, and Class C for unsound material. A clear Class A result usually satisfies lenders, while a Class B or C result can make mortgage finance difficult without further investigation or remedial work.
How much does a mundic test cost?
The cost of a mundic test varies with the size of the property and the number of samples required, and it is usually paid for by the buyer as part of the survey process. It is a specialist test, so it typically costs more than a routine survey add-on. Because the result directly affects whether a lender will proceed, it is worth arranging early, before you are too far into the purchase, so you can make an informed decision.
Can you get a mortgage on a mundic block property?
Yes, provided the test result supports it. A property that tests as sound is generally treated like any other by most lenders, though some remain more cautious than others about the region. Where the result is uncertain or unsound, mainstream lenders often decline, and you may need a specialist lender, further testing, or evidence of remedial work. A broker who understands the South West market can help identify lenders willing to consider these properties.
Buying or selling a mundic property
If you are buying, factor the test into your timeline and budget, and use the result to inform your offer. If you are selling, having a recent clear test available can reassure buyers and their lenders and prevent delays. In both cases, the test result is central, so getting it done by a qualified professional and keeping the documentation is important.
Frequently asked questions
What is a mundic block? It is a building made from concrete containing local mine or quarry waste, common in Cornwall and Devon, which can deteriorate over time and so requires testing before most lenders will lend.
Do all lenders require a mundic test? Most lenders in the affected region require one before agreeing a mortgage, because they need to confirm the concrete is structurally sound.
What do the mundic test classes mean? Results are typically graded as Class A for sound material, Class B for uncertain material that may need further testing, and Class C for unsound material.
Can I get a mortgage if the property fails the test? It is harder. Mainstream lenders often decline uncertain or unsound results, so a specialist lender, further testing, or remedial work may be needed.
For help finding a lender for a mundic or non-standard construction property, speak to our team via the meet our team page or browse our mortgage, property and money advice hub.
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- About adviser Damian Youell
Your home may be repossessed if you do not keep up repayments on your mortgage. Needing Advice is an independent, FCA-regulated whole of market mortgage broker. This article is general information only and does not constitute financial or mortgage advice. Availability and lender criteria vary and can change, and any arrangement depends on your individual circumstances. There is no obligation, and we recommend seeking personalised advice before making any decision.
Damian Youell
Damian is the founder of NeedingAdvice.co.uk and the firm’s Senior Mortgage Broker. He specialises in helping clients across the UK with straightforward and complex mortgage cases, including self-employed applications, adverse credit, buy-to-let, remortgages and first-time buyer mortgages.
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