How to spot YOUR home is at risk of subsidence and fix it without breaking the bank: Our property experts' guide to tackling the problem before it knocks a fifth of the value off your house
One in five homes is vulnerable to subsidence. Discover you have a problem and it can knock a fifth off the value of your home – as fewer people will want to buy it and mortgage providers are less likely to offer a loan.
Fixing subsidence can cost £40,000 or more if you have to bolster the foundations of your home with concrete. But, if you follow our panel of experts’ advice, you can tackle subsidence without breaking the bank.
We spoke to Michael Lawson, chief executive of subsidence adviser Property Risk Inspection, along with Jeremy Rollinson, insurance claims negotiator for Salmon Assessors and Alan Milstein, chairman of the Residential Property Surveyors Association.
Read their top tips below.
Spot the tell-tale signs
A crack in the wall or ceiling is usually caused by natural shrinkage in cold conditions and swelling in hot weather – and such movement is normal for the majority of homes.
Subsidence can be more visible near doors and windows as the frames start to warp
However, if the spaces between these cracks grows to at least 3mm in width you may have subsidence. Other tell-tale signs to raise concern is if this wider crack is diagonal and wider at the top than the bottom – and visible from both outside and inside of the house. Subsidence can be more visible near doors and windows as the frames start to warp and any wallpaper hung on walls might also crease up where the wall meets a ceiling.
The reason for these larger cracks is because the ground on which the property is built has started to sink – and masonry and bricks walls which sit on the foundation have shifted their position. This may first be noticeable when cracks appear on the plaster that covers the walls.
About 70 per cent of subsidence problems are caused by trees or shrubs planted in clay-rich soil. Plant roots soak up water all year round but during dry spells they can shrink the ground because the moisture in clay soil enables it to take up more space – and when water is sucked out by roots the clay soil then shrinks in size.
The roots can have been working their way up to and under a building for many years without the owner being aware they were about to wreak havoc on their property. Among the most likely trees to cause damage are oak, poplar, elm, horse chestnut and willow. For example, an oak root can grow up to four feet below the ground within a decade – and spread out at the rate of a foot a year.
If you have an established 50-year-old tree that is 50 feet from your home the roots could already have reached your property. You may not notice subsidence cracks in the walls of your home until five years later after it has started burrowing under foundations and caused damage.
Which properties are most at risk?
The most vulnerable properties are those with foundations that are less than 3ft deep, which are typically those built in or before the Edwardian and Victorian era. But this does not mean you are automatically safe if you live in a more modern home.
Regions where there is clay in the soil are also where you are most likely to find subsidence issues, which is mostly in the south east of England and around London.
The most vulnerable properties are those with foundations that are less than 3ft deep, which are typically those built in or before the Edwardian and Victorian era
In many cases, removing a tree should take away a potential subsidence issue without the need for expensive work or making a home insurance claim where the initial excess to be paid can be more than the tree bill.
Getting a professional tree surgeon to take down a tree might cost £500 to £2,000. This compares to £40,000 or more required to underpin part of the home and reinforce foundations to stop roots doing more damage. The trade body Association of British Insurers (ABI) says trees should ideally be planted 100 feet from a property.
The Arboricultural Association can provide details of accredited tree surgeons in your region.
Hold your insurer to account
Call your buildings insurance provider if you have signs of subsidence and ask them to visit – and do not take no for an answer.
Jeremy Rollinson, insurance claims negotiator for Salmon Assessors, says: ‘Insurers are often eager to kick claims into the long grass as it saves them money. But be persistent. They might want you to send photos or make a video but there is no substitute to a face-to-face visit.’
He adds: ‘Subsidence can reduce a property’s value by as much as a fifth because it makes it far more difficult to sell – as no one likes the idea of buying a house where thousands of pounds must be spent to get it in good order. You will also struggle to get a mortgage with subsidence.’
Even once the insurance company has visited, and agreed there may be a problem, you must be patient as a professional check and work completion can take years. The ‘diagnosis’ alone can take six months, which might include installing lasers to monitor how and where the property is sinking – and why.
Homeowners should use a surveyor signed up to a trade body such as the Residential Property Surveyors Association or the Royal Institution of Chartered Surveyors
After any necessary work has been completed you may also have to wait a further six months for a ‘certification of structural adequacy’ to show that the property is stable. This is vital when selling the property at a later date without it losing market value.
Rollinson says that insurers will often use this time delay to pressure homeowners into accepting cheaper solutions – or not paying out as much as they should do.
He says: ‘Do not simply accept a first offer as you need to factor in additional costs – not just the essential repair work but necessary cosmetic work to make sure that the house is put back in good decorative order again.’
Michael Lawson of Property Risk Inspection, says: ‘Six out of ten claims are repudiated by insurance companies not willing to spend thousands of pounds underpinning a property foundation when there are much cheaper solutions they suggest, like cutting down trees.’
The ABI says 23,000 claims were paid out in 2022 for subsidence – with the average payout being £9,600. It reveals how the industry is more likely to opt for a cheap solution rather than underpin the home with concrete, which can cost four times the average insurance payout.
A surveyor can pick up potential subsidence problems when you buy a home, but only one in five bother to get a full one. Another problem is they only looking at a snapshot in time – so the surveyor can wash their hands of future subsidence if not noticed at the time.
Alan Milstein, of the Residential Property Surveyors Association, says: ‘Many people put their trust in a valuation of the property – they mistake this for a professional survey.’ He adds: ‘We do not have a crystal ball or x-ray vision and only take a snapshot of a moment in time. We do not know what will happen in the future.’
He suggests using a surveyor signed up to a trade body such as the Residential Property Surveyors Association or the Royal Institution of Chartered Surveyors. They both offer an ombudsman service to help if you feel let down by a subsidence report. But be aware it is hard to hold them responsible for future issues.
According to the Office for National Statistics up to a quarter of all homes do not have cover. This can be an expensive mistake because it can make a property unsafe and impossible to sell unless it gets sorted out.
Why you should always talk to your neighbour
Unfortunately, just because the tree roots do not start from your garden, it does not mean it is not your problem.
Having a good relationship with neighbours is vital at the best of times – but with potential subsidence issues having them on your side can lower disruption and cost.
Lyn Hunter has a 30ft willow tree planted near her property. She feared it could be causing subsidence damage to her home. She was alerted when a three-foot long crack appeared in the eave of her house a year ago.
The 88-year-old retired primary school teacher contacted Money Mail after feeling she had been brushed off by her home insurer Royal & Sun Alliance (RSA) who were initially not interested in coming out to check her £150,000 three-bedroom semi-detached home near Middlesbrough in County Durham. It later blamed ‘miscommunication’ but admitted it had warned Lyn when she called there would be a £1,000 excess bill if she was to claim for subsistence on her £398-a-year home policy.
Lyn Hunter feared a 30ft willow tree planted near her property could be causing subsidence damage to her home
She was alerted when a three-foot long crack appeared in the eave of her house a year ago
In June an assessor gave her home a clean bill of health, suggesting her cracked wall only needed cosmetic repair. But the report came with a caveat: ‘The willow tree of your rear boundary neighbour could have the potential to cause damage in the future.’ It suggested sharing the findings with her neighbour to discuss cutting back or removing the willow.
A challenge for Lyn was the tree at the bottom of her garden was over the fence on her neighbour’s land. She said: ‘When I moved here 30 years ago you could not see the tree but now it is 35ft high and blocks out sunlight. The neighbours are friendly but believe it is not their problem and are unwilling to pay someone to chop it down.’
Lawson says: ‘It makes things more complicated but do not be afraid to contact your insurer if the problem comes from a tree not on your property. You may be able to make a claim on your insurance company – and they in return can sort out the details of who pays. This can be done by them dealing directly with a neighbour’s insurer.’
RSA says: ‘We would approach the neighbour with recommendations and seek co-operation. If they refuse to co-operate, we monitor the situation and may still underpin a property and create a root barrier.’ The insurer says it seeks to cover any costs from the neighbour – and this can be done through their own insurance company.
Lynn says her neighbours are friendly but are unwilling to pay someone to chop the tree down
You are legally entitled to prune back parts of a tree growing over the boundary into your property (as long as there is no tree preservation order). The Arboricultural Association says: ‘You cannot compel the owner of the trees to carry out this work or pay for it. But if your neighbour’s tree is a hazard to your property action can be taken. An arboricultural consultant can offer advice.’
If trees are planted on public land outside of your boundaries, you may face an even bigger headache. Councils can place a preservation order on trees on your property in a conservation area, which adds to red tape.
Lawson says: ‘It might take the council at least three months to respond to a query – and then there could be monitoring measures put in place for a year or more. You cannot do anything on public land without their authority.’