What is mundic, and how do you deal with it on the Cornish property market?

If you’ve ever bought, or considered buying a property in Cornwall, the likelihood is you will have come across the term ‘mundic’ at some point. But what is mundic, and how do you navigate the issue when buying and selling houses in Cornwall? 

Mundic is a Cornish word meaning ‘mining waste’ and refers to a substance used in the concrete block foundations of many properties throughout Cornwall built from the turn of the twentieth century until the 1950s.

Mundic consists of waste rock worked from mining and quarrying, beach gravel and iron containing sulphur, known as Pyrite, which is sometimes referred to as called fool’s gold.

The traditional raw materials to form and mould conventional red clay bricks were not readily available here in the Southwest, so recycling waste from the local mines seemed like an ideal solution, providing a much cheaper and easier alternative.

So, what’s the problem with mundic?

More recently, it emerged that the high levels of minerals in mundic leads to deterioration of these concrete foundations over time. Today within the property market, the term ‘mundic’ is associated with this concrete degradation.

In severe cases, mundic has caused significant complications for property owners, particularly when mortgaging or purchasing buildings. Essentially crumbling away from the ground up, you won’t get a mortgage on a property where mundic is extensive in the foundations.

How are houses tested for mundic?

In the early 1990s, the Royal Institute of Chartered Surveyors and the Building Research Establishment developed a screening test to identify the extent of mundic concrete degrading. 

They created three bands, A, B, and C, with multiple categories within each one. Class B and C homes are unfortunately un-mortgageable. However, those in class A contain only small traces of little concern, and in some cases are unlikely to suffer adverse effects in the future.

The tests cost upwards of £450 (plus VAT), but are a very necessary expense if you’re considering buying a property in Cornwall built during the mundic era. 

Is there a flip side?

For some buyers exploring the Cornish property market now, mundic could be seen as an opportunity for investment, especially when it only exists in a small area of the property. However, it’s important to check the date of the last mundic test undertaken, as it could now have a different classification, particularly if the initial test was done a long time ago.

If you’re considering investing in a property blighted by mundic, you need to weigh up the cost of repair, ensuring it’s less than the reduction in market value (which would be considerably in a property badly affected). It’s also worth noting that the existence of mundic doesn’t stop a property being let to tenants, unless it’s rendered the building structurally unsound.

Mundic made good! 

Architect Andrea Lane has first-hand experience in dealing with mundic during a renovation project. Andrea is a highly experienced RIBA certified architect and is the Owner and Founder of Lane Architects, a studio based in Falmouth which specialises in residential architecture with extensive experience in self-build homes and renovations.

Andrea’s own property, the renovation of which she designed and project managed, began as a mundic bungalow. Extensive testing revealed the original property was in bad shape, so Andrea made the decision to raze the bungalow to the ground, redesigning it into a contemporary three-bedroom dwelling.

“Mundic can be in the walls or foundations or both,” explains Andrea. “It is assessed by a specialist surveyor and graded from light to severe. This grade will determine whether you will be able to get a mortgage on the property or not. Often, on a mortgaged mundic property the mundic will need to be surveyed annually.”

She continues: “If mundic is in the walls, building work can be done to locate, remove and replace the affected blocks, however this can be costly. Mundic foundations work is more invasive and expensive.”

However, Andrea saw an opportunity when looking to embark on her own self-build project. “We looked at the mundic bungalow at 29 North Parade as a good development opportunity as, knowing we wished to build our own home, the main difficulty was finding a suitable plot.”

We were able to use the sloping site of the bungalow plot to design a split-level home in a highly desirable location. The demolition and rebuild took 18 months, paid for with a self-build mortgage.”

Andrea’s experience just goes to show that, with Cornish property in such high demand, it pays to think outside the box when searching for your perfect home!

Here at Harding Laity, we are one of Cornwall’s leading estate agents with offices in St Ives and Wadebridge. If you’re looking to buy a house in Cornwall or sell with a Cornish property specialist and are concerned about issues such as mundic, our team is on hand to give you top-tips. Why not get in touch and start the conversation today!