What Is Subsidence?
Subsidence is when the ground beneath a property sinks. This can destabilise the building, cause cracks in walls and floors, and lead to ill-fitting doors and windows. Subsidence is more common when houses are built on clay soils which expand and contract seasonally. The typical scenario is that clays expand in winter when the weather is wet and shrink in summer when the weather is drier. It is the seasonal shrinking and swelling of the soil that causes movement and damage to buildings.
A History Of Subsidence
We have probably all known old terraced houses in which doors did not fit and floors were uneven and it goes without saying that subsidence will have existed as long as buildings have been built. However it is easy to put a date on when subsidence first became a problem and that was in 1971 when insurance companies started to add subsidence cover to household insurance policies.
The rise in home ownership in the 1970’s was, to some extent, driven by mortgage lenders who saw adding subsidence to insurance policies as an additional safeguard to their investment, exposing them to little additional risk! That changed after the drought of 1976 when the extensive shrinkage of clay subsoil resulted in a considerable number of claims. At that time the policy of many insurers was to carry out quite major repairs and underpinning to properties that displayed even minor damage and this obviously resulted in substantial expenditure.
This then created a situation where insurers became very reluctant to offer cover to new policyholders on properties that had shown any signs of previous movement, as they had become in today’s parlance ‘risk adverse’. As mortgage lenders also wished to protect their position, they would be equally reluctant to lend on a property where it might be difficult, if not impossible, to obtain insurance against subsidence.
These concerns were in turn passed onto Valuation Surveyors who, mindful of their professional indemnity insurance, tended to report even minor cracks as potential subsidence issues. Thus in a few years the situation changed from one in which no one worried too much about a few cracks, to a situation where everyone became paranoid about even a hairline crack in case it would render their property uninsurable and hence unsaleable.
Subsidence Claims Today
Claims normally begin when properties are re-decorated or put on the market. At this point a homeowner may worry about cracks that they had not really noticed before or a mortgage lender for a prospective purchaser may send a ‘Valuation Surveyor’ who reports evidence of crack damage or previous movement.
On receiving notice of a potential claim insurers will usually appoint a Loss Adjuster to investigate on their behalf. The Loss Adjuster will visit the property and prepare a report recommending what further action needs to be taken. It is very difficult to arrive at any firm conclusions from one visit, particularly if the damage is relatively slight, so it will be quite normal for the Loss Adjuster to recommend that further investigations are carried out. Typically the investigations would involve establishing the depth of the foundations, recording the type of subsoil, recording any trees or major shrubs on the site and analysing soil samples and any roots recovered from the investigations.
It would also normally be recommended that the cracks are monitored. This involves taking detailed measurements at set periods to establish whether the cracks are opening, closing or stabilising. It may also be suggested that a ‘level monitoring’ exercise is carried out. This would establish whether the building is rising, falling or staying in the same position relative to a fixed point. With modern measuring equipment crack and level monitoring is carried out to a very fine degree, often talking about movements of a fraction of a millimetre. This level of investigation takes a considerable period of time, months or even years, and the costs can run into several thousand pounds, often outweighing the cost of the eventual repairs.
If the trees are on adjoining land, the insurers will have to prove that they are implicated and ask the adjoining landowner to remove them. This request is often accompanied by the threat of action to recover any losses if the landowner does not remove the trees and sometimes this can be quite intimidating. Most homeowners, receiving a legal letter of this sort will, unfortunately, feel obliged to comply without challenging it.
More often than not the tree thought to be causing the subsidence is a street tree owned by the council. This makes the council liable for any damage and if the council refuses to fell the tree the insurers will threaten to take the council to court. It only takes a small bit of tree root found under a property for the insurers to win such a court case, thus rendering the council liable for all the costs: the extensive monitoring, underpinning, re-homing of residents while the work is being done and the legal costs incurred. These sums can amount to hundreds of thousands of pounds. It is not surprising then that councils usually go ahead with such tree-felling without challenging the Insurers. It is sad to see that the regular excessive pollarding of street trees which we see today in so many towns is also done as a preventative measure, to make sure that, by reducing the foliage, the trees’ demand for water will also be reduced and so will the demands of insurance companies.
Insurance companies are businesses that are, quite understandably, looking to thrive and make a profit. Obviously, they will look to minimise the amount that they have to pay out under any particular claim. To a large extent, this is why the removal of trees is often suggested, as it may cure the problem and has no cost implications for insurers. Some insurance companies even skip the costly investigations, demanding that trees are removed as a first step to see if this remedies the problem.
It does not matter to Insurers that the removal of trees is always somewhat experimental. There is no guarantee that removing trees or shrubs will have the desired effect and even if the property does stabilise after tree removal there is no way of proving that the building would not have stabilised of its own accord anyway. When looking at clay subsidence there are so many variable issues, such as the type of clay, the depth of foundations, climatic conditions, underground water sources and slope of site that it is never going to be possible to say conclusively that removal of trees alone is the problem. All these factors should be checked before a tree is needlessly felled.
Under current legislation buildings have all the legal protection and trees have none. Insurance companies currently have no obligation to look at the wider ecological issues of tree removal; they have only to consider their interests and those of their shareholders and they have to keep their costs down to be competitive. It will only be through powerful and strongly worded legislation that we will see a SHIFT in procedures relating to trees and subsidence.