uk sinkhole
© Colin Parsons/PAOne of two sinkholes that opened on farmland between Sittingbourne and Faversham in Kent.
Once a rare occurrence, a recent spate of holes suddenly appearing raises some tricky questions about insurance

Sinkholes weren't something the average householders thought about in the past - and despite a spate of recent occurrences - are very rare. But if the ground does open up and swallow your house, there is good news and bad news: while insurers will usually pay for your property to be repaired, they are unlikely to cough up for any damage to your garden.

Sinkholes develop when underground soil and rock are eroded by water or rain and the recent wet weather means that more properties than usual could be in danger. "Damage that a sinkhole causes to your property will be covered by buildings insurance," says a spokesman for the Association of British Insurers. "Your buildings policy will not cover repairs needed if there is no damage to your home, such as if a sinkhole appears in your garden."


Comment: While the recent wet weather may certainly be a factor, there is something else going on here. Perhaps the sinkholes and the crazy weather actually share a common cause, likely electrical in nature.


This insurance gap can result in large losses, as one unfortunate resident of Barnehurst in Bexleyheath recently discovered. On 5 February a hole 17ft deep and 10ft wide suddenly appeared in the garden of Gretel Davidson's 1930s house. She contacted her insurer Halifax, presuming she'd be covered by her buildings policy. However five days later, she received a letter stating: "Damage to garden features is excluded under your policy unless your home is damaged by the same cause and at the same time. In this instance as there is no damage to your home the cost of filling the void is not covered under your policy."

She is now left with a £10,000 bill to fill in a hole that is getting bigger by the week. The single mum, who only recently left hospital with a heart condition, must now work extra shifts as a radiographer to fund the work. "The law needs to be changed because so many people don't realise that they're not covered," she says.

Halifax confirms its approach. "Following a thorough investigation our engineers are confident that the sinkhole had not caused any damage to the property and poses no threat to the structure of the home, therefore it was not covered by the insurance policy."

The insurer's approach is not unusual. Direct Line Insurance, which through its subsidiary UK insurance, underwrites buildings insurance for Nationwide, Churchill, Privilege, Virgin, Royal London, RBS and NatWest, confirms: "We would only be involved if the fabric of the building is damaged."

And it doesn't apply just to sinkholes - no subsidence damage to a garden alone is covered by buildings insurance unless it also affects the house at the same time. This includes damage to swimming pools, patios, hot tubs, trees, plants, ponds etc. This is also the case for earthquake and flood damage. Storm damage to gates, fences and boundary walls is normally not covered, although some items of garden furniture can be insured under contents insurance.

In theory homeowners who want to cover their garden against damage cause by sinkholes need to take out extra insurance, however none seems to be available. The British Insurance Brokers Association (BIBA) was unable to identify a single specialist insurer that might take on this risk.

The lack of such cover in the UK and the widespread ignorance about the limits of buildings insurance among consumers, is something that the financial regulator the Financial Conduct Authority seems unconcerned about. "The FCA rules outline what is expected of companies when they are selling insurance to ensure that customers are treated fairly and given clear and accurate information. The decision to offer certain insurance products is a commercial one for insurance companies," it says.

How great is the risk?

Although "sinkholes" have become an all-encompassing term for cavities in the ground that are suddenly exposed, technically, the term is used only for naturally occurring cavities; ones caused by mining activity are known as "crown holes". It is difficult to predict where either will appear but there are some pointers.

Dr Vanessa Banks from the British Geological Survey (BGS) says: "We do have a map providing susceptibility assessments but this is not the same as a risk assessment. We as geologists can identify areas that are most prone, due to underlying soluble rocks. However, to provide a detailed risk assessment you'd need to know the history of the area as some of the risk factors are human-made, such as mining hazards caused by medieval mining for chalk."

According to the BGS, prone areas include the Mendips, parts of Wales, the Peak District, and the northern Pennines including the Yorkshire Dales, parts of Dorset, Hampshire, the Chilterns and Ripon.

Dr Clive Edmonds, a geo-technical engineer who has been studying these holes for 25 years and who works for consultancy Peter Brett Associates, estimates there are at least 32,000 natural occurring holes and 15,000 non-coal mines or pits dotted around the UK mainland that have been identified.

Land search results by Landmark or GroundSure, which provide environmental risk information and digital mapping, could provide some indication if your property is at risk from a known hole. However, new holes are constantly being discovered, so this isn't foolproof.

The recent wet weather has made the problem worse as Edmonds says: "In an average year I'd expect half a dozen holes to appear in the south that might cause damage. But since July I've dealt with more than 20 holes in southern England."

Worryingly, Edmonds says more rain will bring more such holes.

How can you protect yourself?

The Council for Mortgage lenders advises: "We would suggest to borrowers to get the best building insurance cover they can, and be sure exactly what the insurance covers."

In addition, those purchasing a property should check that it is insurable at normal rates and that there is no historic mining activity or subsidence.

Those who wish to check their current property against a database can contact Peter Brett Associates, which holds a national databases of non-coal mining and natural cavities. Alternatively, you can use Landmark or GroundsSure.

For those purchasing a property near such a hole, a specialist ground survey can be carried out to check ground stability, but will cost a minimum of £500.

Practical safety measures to avoid triggering a hole in an area prone to subsidence include fixing water leaks from faulty guttering or downpipes, avoiding running a hose for extended periods, or emptying swimming pools on to the garden.