12/12/2016
Building and home owners who discover subsidence in their property often wish the ground would swallow them up. Even with the most helpful insurance companies, claims can take up to three years to resolve. And if you find your insurance policy will not cover your subsidence issue – expect major legal battles and repair bills.
Surveyors define subsidence as the downward movement of the site on which a building stands - where the soil beneath the building's foundations is unstable. The major cause of subsidence problems according to insurance companies is tree roots. Leaking drains can also cause subsidence issues and there are many instances of buildings being constructed over disused coal mines, quarries and even rubbish tips. In these situations, the gap below ground level can cause the property above to sink.
Subsidence risk factors
Older properties are most at risk of subsidence. This is because the type of land a property is built on is very significant. Clay and loamy soil (a mixture of sand, clay and water) are most vulnerable to moving and causing subsidence. Newer homes and commercial buildings tend be constructed on virgin chalk and gravel; less likely to contract and crack when water is extracted and heat applied. Homes built prior to the second world war were also constructed on shallower foundations than modern properties, increasing their susceptibility to subsidence.
However, a new property build on soil that causes subsidence is unlikely to fair well. Modern buildings have a more rigid structure, leaving them more vulnerable to cracking.
The proximity of trees and shrubs to the structure plays a major role in subsidence in the UK, especially if the property has been constructed on clay. Tree roots absorb water for photosynthesis and moisture evaporates from leaves through transpiration. The active period is predominantly in spring and early summer when tree growth is at its maximum. Larger trees in shrinkable clay soil can extract sufficient moisture to cause significant soil shrinkage (a mature deciduous tree can remove in excess of 50,000 litres of water a year).
Recognising subsidence
Tell-tale signs of subsidence include:
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large cracks that form from smaller versions, especially those forming in the corner of windows and door openings
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doors and windows sticking (caused by the movement of the building)
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cracks that are more than 3mm wide and often wider at the top
If you have constructed an extension on your property, cracks appearing where it joins to the house may indicate that the extension is being ‘pulled away’ from the main building.
It is important to note that not all cracks indicate subsidence, for example, new-build homes often experience cracks caused by ‘settlement’ which is a normal part of the structure bedding down. Changes in temperature can also lead to cracks as can slight seasonal movement.
The importance of a survey to pick-up signs of subsidence
If you are purchasing an older property for private or commercial purposes, it is crucial to invest in a quality survey, be it structural, valuation or a comprehensive home-buyers report.
If subsidence is discovered, obtaining building insurance will prove extremely difficult.
Repairing subsidence
If you already own a property and suspect subsidence, a structural survey will either confirm or allay your fears. If subsidence is found you should contact your insurer immediately. The quicker subsidence is diagnosed, the more likely that it can be rectified and most insurance companies will send a loss adjuster (or similar professional) to inspect your home or commercial property to assess the potential cost.
Underpinning, a process in which the buildings foundations are deepened, may be required in severe cases of subsidence. This is an expensive and disruptive procedure, (especially if the premises are occupied by commercial entities). Fortunately, it is estimated that underpinning is only required in 10% of subsidence cases.
If tree roots have caused subsidence, removing the tree may resolve the problem and prevent the damage developing into a major problem. However, in rare cases this can lead to the antithesis of subsidence known as 'heave'.
Heave is where, instead of downward movement due to moisture reduction, the ground beneath a property swells up with excessive moisture and is caused by the absence of a tree that used to keep the moisture levels low. An arboriculturist (tree specialist) will advise you on the best course of action to take.
In summary
If, upon the discovery of subsidence, you and your insurer deal with the matter swiftly, a relatively inexpensive, un-intrusive solution may be found. Engaging an expert solicitor who understands the nature of subsidence claims can help speed up the resolution and advise on any policy issues encountered during the process.
Fisher Scoggins Waters are a London based law firm who are specialise in property damage law. If you would like more information on claiming for building damage caused by subsidence, please phone us on 0207 993 6960.