Subsidence fears set off home insurance tremors

THIS summer's drought conditions could help force a huge shake- up of home insurance premiums, as underwriters attempt to pinpoint risks, in fear of a rash of subsidence claims. Building premiums in high-risk heavy clay areas could rise to more than pounds 3,000 a year, making homes virtually impossible to sell, while other home-owners could find their premiums slashed to just pounds 50, according to one industry expert.

The dry spell should not itself cause severe subsidence problems, because of the preceding wet winter. But if it is followed by a dry winter and another dry summer, then it will be a disaster for home-owners and insurers. Minor cracks will appear in properties this year, especially in newer homes, which owners should watch and measure.

"If the present dry weather stays with us for four months, then there will be the same problems as in 1976, 1980 and 1989," says Malcolm Hollis of Reading University. "The problem is with the clay areas in the South- east of England, from the brickfields of Bedford to Southampton. You would be looking for clay becoming dry at the area below the foundations of buildings, about 2-4ft down. Summer dryness goes down to about a foot.

"The nature of the building will influence how it is affected," Professor Hollis says. "A modern home is very brittle, and will see damage. Victorian buildings can withstand a lot more. The worst thing is foliage, which accelerates the reduction in water. Trees are moving into autumn early with less water around. Trees in spring look for water far more than now, with the greatest damage from root spread."

Even so, the dry summer following a wet winter causes its own problems, with clay swelling and then shrinking, and the soil losing as much as a third of its volume. Most homes affected will sink uniformly into the soil, but some, built on the edges of differing soil structures, will crack. There is also a fear that some homes dating from the 1980s boom were built on unsuitable land, which will only now become apparent.

David Tuffin, of surveyors Tuffin, Ferraby and Taylor in London, says: "Insurers should not leap forward and underpin, which is what was done in 1976, costing insurers an arm and a leg. With some properties, particularly Victorian ones, you get movement one year, movement back the next. The watchword is to measure, photograph and monitor. It is movement which is progressive that is a real problem. If it is a 1mm crack it can be ignored; 3-5mm is no more than cosmetic; 25mm wide is a serious problem; if it is more than that, run out of the door and get clear."

Insurers report that subsidence claims so far this year are low, but in itself that means little - in bad years it has taken some months before the claims have rolled in. The weak housing market also defers the impact, with between 25 and 40 per cent of claims arising out of home buyers' surveys. Surveyors are doing a third of the amount of surveys they did in the boom.

Several insurers are experimenting with computer models developed by the British Geological Survey and by Cranfield University that could enable underwriters to predict which homes are most likely to subside. If tests go well, then from next April home-owners will begin to find premiums vary more, as insurers replace the current system of assessing risk by postcode.

Cranfield's computer analysis is being marketed by Ventech, not only to insurers but also to surveyors and individuals, who can obtain reports on individual properties for pounds 75. Director Chris Venvell says: "The next best thing is a soil sample expert at pounds 400-500. Our report could save pounds 20 a year on premiums, if the report shows a lower subsidence risk than the insurer has assessed. A house-buyer has used one of our reports to negotiate a reduction in price."

Mr Venvell predicts a dramatic widening of premiums, and insurers admit substantial increases are likely in high-risk areas. Mr Tuffin, however, suggests that claims for the computer modelling are exaggerated. "It is a fancy gizmo. You really need someone to dig a hole, otherwise you don't get much more than buying a geological survey map."

Another problem is that although shrinking and swelling of clay is the most common cause of subsidence, it can also be caused by landslip, mineworkings, heave, corrosion, and erosion, which currently cannot be detected by Ventech's model.

q Contact points: Ventech, 01789 488707; Property Underwriting Services (for soil surveys), 01424 733727; the British Geological Survey, 0115- 936 3166.

Start your day with The Independent, sign up for daily news emails
i100 In this video, the late actor Leonard Nimoy explains how he decided to use the gesture for his character
Robert De Niro has walked off the set of Edge of Darkness
news The Godfather Part II actor has an estimated wealth of over $200m
Arts and Entertainment
Fearne Cotton is leaving Radio 1 after a decade
radio The popular DJ is leaving for 'family and new adventures'
Robbie Savage will not face a driving ban
Life and Style
Nearly half of all young people in middle and high income countries were putting themselves at risk of tinnitus and, in extreme cases, irreversible hearing loss
health Nearly half of all young people in middle and high income countries are at risk of tinnitus
It was only when he left his post Tony Blair's director of communications that Alastair Campbell has published books
people The most notorious spin doctor in UK politics has reinvented himself
ebooksA special investigation by Andy McSmith
Arts and Entertainment
arts + ents
Life and Style
Arts and Entertainment
James Franco and Zachary Quinto in ‘I Am Michael’
filmJustin Kelly's latest film tells the story of a man who 'healed' his homosexuality and turned to God
Arts and Entertainment
Public Service Broadcasting are going it alone
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs Money & Business

SThree: HR Benefits Manager

£40000 - £50000 per annum + pro rata: SThree: SThree Group have been well esta...

Recruitment Genius: Office Manager / Financial Services

£30000 - £37000 per annum: Recruitment Genius: Established in 1999, a highly r...

Jemma Gent: Year End Accountant

£250-£300 Day Rate: Jemma Gent: Are you a qualified accountant with strong exp...

Jemma Gent: Management Accountant

£230 - £260 Day Rate: Jemma Gent: Do you want to stamp your footprint in histo...

Day In a Page

HIV pill: Scientists hail discovery of 'game-changer' that cuts the risk of infection among gay men by 86%

Scientists hail daily pill that protects against HIV infection

Breakthrough in battle against global scourge – but will the NHS pay for it?
How we must adjust our lifestyles to nature: Welcome to the 'Anthropocene', the human epoch

Time to play God

Welcome to the 'Anthropocene', the human epoch where we may need to redefine nature itself
MacGyver returns, but with a difference: Handyman hero of classic 1980s TV series to be recast as a woman

MacGyver returns, but with a difference

Handyman hero of classic 1980s TV series to be recast as a woman
Tunnel renaissance: Why cities are hiding roads down in the ground

Tunnel renaissance

Why cities are hiding roads underground
'Backstreet Boys - Show 'Em What You're Made Of': An affectionate look at five middle-aged men

Boys to men

The Backstreet Boys might be middle-aged, married and have dodgy knees, but a heartfelt documentary reveals they’re not going gently into pop’s good night
Crufts 2015: Should foreign dogs be allowed to compete?

Crufts 2015

Should foreign dogs be allowed to compete?
10 best projectors

How to make your home cinema more cinematic: 10 best projectors

Want to recreate the big-screen experience in your sitting room? IndyBest sizes up gadgets to form your film-watching
Manchester City 1 Barcelona 2 player ratings: Luis Suarez? Lionel Messi? Joe Hart? Who was the star man?

Manchester City vs Barcelona player ratings

Luis Suarez? Lionel Messi? Joe Hart? Who was the star man at the Etihad?
Arsenal vs Monaco: Monaco - the making of Gunners' manager Arsene Wenger

Monaco: the making of Wenger

Jack Pitt-Brooke speaks to former players and learns the Frenchman’s man-management has always been one of his best skills
Cricket World Cup 2015: Chris Gayle - the West Indies' enigma lives up to his reputation

Chris Gayle: The West Indies' enigma

Some said the game's eternal rebel was washed up. As ever, he proved he writes the scripts by producing a blistering World Cup innings
In Ukraine a dark world of hybrid warfare and murky loyalties prevails

In Ukraine a dark world of hybrid warfare

This war in the shadows has been going on since the fall of Mr Yanukovych
'Birdman' and 'Bullets Over Broadway': Homage or plagiarism?

Homage or plagiarism?

'Birdman' shares much DNA with Woody Allen's 'Bullets Over Broadway'
Broadchurch ends as damp squib not even David Tennant can revive

A damp squib not even David Tennant can revive

Broadchurch, Series 2 finale, review
A Koi carp breeding pond, wall-mounted iPads and a bathroom with a 'wellness' shower: inside the mansion of Germany's 'Bishop of Bling'

Inside the mansion of Germany's 'Bishop of Bling'

A Koi carp breeding pond, wall-mounted iPads and a bathroom with a 'wellness' shower