Did you know that Mundic is a Cornish slang word? From about the 1900’s to the 1960’s some of the waste from the Cornish mines was used in the making of concrete blocks. It probably seemed like a good idea at the time and must have felt like a cheap, early form of recycling.
However, as the years passed, it was discovered that some of the bits of iron ore used in the mix became unstable when wet. This really came to light as we started to install unventilated double-glazing into our houses in the 1970’s. We might well have been nice and warm, but the moisture trapped in the houses made the walls damp and consequently the concrete blocks started to degrade and crumble.
You will probably find that if you are buying a house in Cornwall built between 1900 and 1965, your mortgage company will ask that you have a Mundic test. The test costs approximately £350 and will involve a specialist drilling holes and taking samples of the concrete. The concrete is tested and the results will fall into 4 classes: A and A/B will be sound and safe, whilst B will be sound but likely to cause problems in the future and lastly C which is clearly unsound.
Houses that are affected by Mundic are generally sold at a lower price because of the difficulties of getting a mortgage, which means if you are a cash buyer, you may well pick up a bargain. It might be that just one wall needs replacing or in the worst cases, you may wish to consider re-development of the site.
The good news for sellers, according to Cornwall Consultants, is that 80% of the 14,000 houses they have checked, come back with an class ‘A’ and only 5% end up with a class ‘C’. If your house, was to fall into either the B or C classes, then you should have a chat with your Estate Agent who can advise you on what you should do next and how it might be best to help you market your house.