Subsidence claims are typically amongst the most expensive home insurance claims. Problems arising from subsidence may be difficult to spot and develop only over a number of years. Making repairs and finding remedies are also likely to be expensive – which is why some home insurance policies may exclude clover for subsidence and why those that do usually impose at least a £1,000 - £5,000 excess on each claim.
This year has seen a notable upsurge in the number of subsidence claims.
Why is that – and in what areas are homes most likely to be at risk?
Risk of subsidence is commonly attributed to a number of factors, some of which may stand up to closer scrutiny, but some which might also be based on popular misconceptions:
- a home – or any building for that matter – might be affected by subsidence in practically any area of the country;
- this is illustrated in geological maps prepared by the website Geobear, showing those areas reckoned to be at greater risk;
- what these show, however, are areas of predominantly clay, sandy or chalky soils, which are said to contribute to unstable conditions for the foundations of buildings;
- soil conditions alone, however, are rarely the cause for subsidence, since any settlement of the building is likely to be reasonably even across the whole of its footprint;
- nevertheless, there is evidence that the recent spell of long, hot, dry summers has contributed to soil shrinkage across belts of predominantly clay soils;
Trees and large shrubs
- a more common problem is the presence of trees and large shrubs growing in close proximity to the building;
- some trees, in particular oaks, poplars, and willows, have long root structures (of 30 metres or more) which soak up a considerable volume of water from the ground – as much as 50,000 litres a year;
- the absorption of water by the roots – especially the thin, fibrous roots at the ends of the root bole – steadily shrinks the surrounding soil and this may lead to the collapse of the foundations of a building (soil shrinkage is responsible for 75% of all instances of subsidence, according to Subsidence Support;
- recent years have seen an increase in the number of extensions built onto homes in the UK;
- not all of these works have been to the highest building standards and inadequate or poorly-prepared foundations on unsuitable ground may be contributing to the recent spate of subsidence claims;
Blocked and collapsed drains
- when drains to your home become blocked or suffer a collapse, the accumulation of ground water may be sufficient to wash away the ground supporting the foundations – especially if your home is built on lighter, sandy or chalky soils.
Subsidence is a problem which may develop over a number of years, but in an uneven and irregular manner. Some years, for instance, further settlement may seem to have stabilised, only to recur once again when weather conditions also change – bringing either prolonged periods of drought or flooding.
It is these changes which may have contributed to the recurrence of subsidence problems and the current upsurge in the number of related insurance claims.