Figures from the ABI show a 50% increase in the number of claims for subsidence since 2002, and last year alone, UK insurers paid out £302 million for subsidence claims.
Neil Curling, senior structural claims manager, Halifax Home Insurance, said: "People don't knowingly cause subsidence, but there are ways homeowners can help to reduce the risk of such damage to their home to avoid the costs, inconvenience and inevitable worry that subsidence damage brings."
In severe cases, subsidence can cause serious structural damage, and can even completely destroy a property. As global warming continues, the problem is expected to become even more prevalent.
During the hot summer months, the risk of subsidence increases as vegetation in the garden is growing rapidly and demands more moisture, when at the same time the weather is at its driest. Properties in the South East are particularly at risk, due to the higher prevalence of clay based soils in the region which shrink as they dry out. Some 70% of all subsidence claims are in areas of shrinkable clay soil. As a general rule, if soil can be rolled into a ball easily, it is likely to have a high clay content.
Curling explained: "Large areas of the country are built on clay subsoil, which is prone to shrink and swell as it dries and re-hydrates. People will often see cracks appear in their gardens during summer, which is indicative of shrinkage of the clay. It's not the clay itself that causes the problem, but trees and other vegetation extracting moisture from it.
"Signs that a property might be suffering from subsidence include cracks in walls, particularly if they are start from corners of windows or doors which themselves may become difficult to open or close. The good news is there are there several measures homeowners can take if they are worried, which can go a long way towards avoiding a problem."
Halifax Home Insurance recommends checking the following:
- When buying a property, check the survey for information on historical activity such as mining. Around 15% of subsidence claims are due to previous mining activity beneath a property, so don't skimp on these important searches.
- A survey of the drainage of the property can identify risk of subsidence caused by water leaking into the soil beneath.
- The local Water Authority can carry out checks on the incoming water main.
- 15% of subsidence claims are caused by water washing away some of the finer soil in the ground.
- Tall trees close to the house can be bad news, particularly for homes built on clay subsoil. They take water out from the ground and cause it to shrink and move. Tree removal solves 84% of tree-related subsidence claims. If removal is not possible, reduction followed by regular maintenance may be the next best thing, but this is uncertain and ongoing tree maintenance can become expensive.
- If in doubt, contact your insurer as soon as possible. The sooner the cause is identified and remedied the sooner the repairs can be undertaken.
- When planning where to plant new trees, bear in mind that some species can grow very large and can initiate subsidence.
