Protect your home from subsidence

29 June 2009

Homeowners are being warned of the danger of subsidence this summer, after the Met Office predicted July and August are set to be warmer and drier than the average British summer.

While 2007 and 2008 saw two of the wettest summers on record, with flooding hitting many parts of the UK, this year is expected to be considerably more Mediterranean. While this is great news for barbecue fanatics and people planning a ‘staycation’, it also poses a serious threat of structural damage to property.

Hot weather can cause land to dry out and become unstable, causing subsidence – literally the shrinking of land. Homes near trees are particularly at risk because their roots grow during dry periods, in search of moisture.

Subsidence can cause serious structural damage and can even completely destroy a property.

According to RIAS, a specialist provider of insurance for the over 50s, property in Chelmsford, Colchester, London and surrounding areas, Milton Keynes, Peterborough and Southend-on-Sea are all at risk of suffering subsidence this summer.

However, the housing boom seen in the past decade could put more homes at risk, as new build properties are no less at risk of subsidence than older ones. There are concerns that building on land that is not ideal for supporting property could mean hundreds of homes may fall victim to subsidence this summer and in the future.

Beat subsidence

Anyone in the process of buying a property should be on their guard against subsidence – as well as looking out for physical evidence, you can find out whether homes in the local area have been affected by checking The Land Registry.

Your surveyor is likely to also be on the look out for any subsidence issues, and you can ask your solicitor about doing further checks if this is a concern.

According to Halifax, around 15% of subsidence claims are due to previous mining activity beneath a property. When buying a property, make sure you check the survey for any information relating to mining in the area.

The soil type around your property will give you an indication of how much risk you have of subsidence. Areas with high concentration of clay soils, those with a high sand or gravel content, or chalk are most at risk.

Neil Curling senior structural claims manager for Halifax home insurance, says: "Large areas of the country are built on clay subsoil, which is prone to shrink and swell as it dries and re-hydrates. It's not the clay itself that causes the problem, but trees and other vegetation extracting moisture from the clay is all too often a recipe for subsidence damage."

For existing homeowners the most important thing you can do in the fight against subsidence is to make regular checks of the external walls of your home. If you notice any cracking in the walls then it’s probably best to consult a qualified builder to find out the cause.

Steve Sweeney, head of home insurance at price comparison website, says: "The most common sign of subsidence is cracks appearing in the wall, especially around the door and window frames. However, homeowners or buyers should only be alarmed when cracks are wider than a thumb as some cracking will occur naturally in buildings.”

Damaged or leaking drains can also increase the risk of subsidence, as these weaken the ground beneath the foundations. Again, be aware of any problems regarding your drains and get them repaired as soon as possible. RIAS recommends you contact a surveyor or the Institute of Structural Engineers if there is evidence of serious erosion of the soil.

Trees close to property are one of the main causes of subsidence. You can eliminate the risk of tree-related subsidence by removing trees; if this is not possible, then regular maintenance such as pruning may help reduce the risk. However, Neil Curling, senior structural claims manager for Halifax home insurance, points out this will not completely remove the risk of subsidence, and can be expensive in the long term.

If you suspect that your property is at a high risk of subsidence, then you could consider underpinning – this is where the foundations are bolstered using concrete. Contact a reputable building company for a quote, and make sure you keep all receipts and certificates.

If subsidence wasn’t bad enough, a hot, dry summer followed by a wet winter can significantly increase the risk of flooding, according to price comparison website

Darren Black, head of home insurance at, explains: "Flooding is no longer confined to the current flood zones and, with wetter weather being predicted for the future, more houses are at risk."


Building insurance will protect you financially against subsidence, but be aware than not all policies will include cover for this automatically. Sweeney recommends homeowners check the small print of their building insurance to make sure they are covered against subsidence.

If your property has suffered subsidence in the past – or you live in an area that is deemed at risk from subsidence - then you may be refused insurance by mainstream providers. However, Sweeny says specialist insurers may be able to help, although you may have to pay a higher premium for cover.

There have been 144,000 subsidence claims in the past four years, according to the Association of British Insurers, and 2009 is expected to see a sharp increase in claims.

Curling says: “Signs that a property might be suffering from subsidence include cracks in walls, particularly if they start from the corners of windows or doors which themselves may become difficult to open or close.”
If you think your property has suffered subsidence, you must contact your home insurer as soon as possible. This will enable you to identify the cause of any cracks and organise the necessary repair work.

Be aware that most insurance companies will monitor the development of cracks over time.

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