When housing subsides, the subsidence needs to be stopped before the property is damaged further. In the past, it was standard practice for underpinning to be carried out. That is the support of the building’s foundations by introducing strengthened foundation base to carry the loads of the existing building. Nowadays, underpinning is specified by building insurers only in the most serious of cases. more ....
When housing subsides, the subsidence needs to be stopped before the property is damaged further. In the past, it was standard practice for underpinning to be carried out. That is the support of the building’s foundations by introducing strengthened foundation base to carry the loads of the existing building. Nowadays, underpinning is specified by building insurers only in the most serious of cases.
Building insurers are also making distinctions between subsidence and settlement. The Oxford English dictionary doesn’t help the poor old house owner or his surveyor in advising on this distinction. A recent case Woodward Chartered Surveyors dealt with in Pinner appears to reflect generally the modern insurance industry’s position on what they are prepared to underwrite:
‘Settlement’ is applied to the failure of the components of a building, which is not covered under the policy.
‘Subsidence’ is used where the building is damaged by a failure in the ground and is covered in most policies.
Our counter argument to the insurers in the Pinner case was that their diagnosis of “settlement” (not covered by the policy) was caused by “subsidence”, in other words the failure of lintels and beams had been caused by extensive movement of the foundations upon the shrinkable clay subsoil. And here is the point: in diagnosing the cause of a defect: it is not always possible to disentangle various sources of the cause a building defect.
It is more normal now for building insurer to identify the cause of the subsidence and to stop its effect on the property by, for example, removing or pollarding vegetation, or repairing leaking drains. Some consumers feel that anything less than underpinning is an inadequate repair. Most building insurance policies, however, will only cover the costs of repairing the damage caused by subsidence.
In practice, so that the repairs are effective, the insurer needs to ensure that the property is stable. To do this, insurers will normally pay for any works needed straightaway to stabilise the property. They may only pay for works needed to solve the immediate problem and not to prevent the possibility of any future subsidence.
In the majority of cases we see, underpinning is not needed to stabilise the property and would be considered preventative action, which is not covered under the insurance policy.
If an insurer uses a method other than underpinning, as surveyors/engineers we will consider whether the method is adequate to stop the movement – or whether expert evidence indicates that underpinning will be more appropriate, taking into account all the circumstances of the case.
In such areas as Harrow, Pinner, Northwood and Ealing, the most common cause of the movement will be inadequate depth of foundations on a shrinkable clay sub soil, but there are many and varied causes, which may combine to confuse the situation (overloading, thermal movement and shrinkage, and sulphate attack). Where it is demonstrated (usually after monitoring) that the structural movement is serious and is of a progressive nature we need to consider the different types of underpinning.
Clearly this is a complex area and if you think your home is moving due to subsidence, we advise you seek the advice of a Chartered Surveyor immediately.