What is subsidence?
Subsidence is when the foundations of your home slowly sink into the ground.
How does subsidence happen?
Subsidence usually happens as a result of issues with the soil around your building. When the soil is too dry or the structure is damaged, it isn’t able to support your property – so the building’s foundations begin to sink.
What causes subsidence?
Subsidence is usually caused by at least one of the following factors:
- Clay soil: Clay contains a lot of water, so clay-rich soils are particularly vulnerable to structural changes if there’s a sudden dramatic change in moisture levels
- Trees: Tree roots sap moisture from the ground, which can cause dryness in the soil, and, in severe situations, structural changes that lead to subsidence
- Heat: During periods of hot or dry weather soil shrinks, while wet weather allows it to expand as it absorbs water again – a cycle which normally evens out any damage. However extended hot periods can dry the soil out and shrink it without letting it recover properly
- Escape of water: In some instances, excessive moisture can cause subsidence rather than dryness. If water leaks underneath your home, for example from a broken drain or pipe, it can soften the soil – leaving it more susceptible to sinking foundations
- Solution features: A solution feature is an underground cavernous structure created by the erosion of soil beneath the ground, which can collapse and lead to subsidence in buildings above ground. These often happen in limestone or chalk-rich ground
- Mining: Underground mines, even unused or deserted ones, can sometimes collapse and cause subsidence in buildings above the ground
- Poor ground: Properties do generally ‘settle’ into the ground as a result of the weight of the building itself. However this can lead to subsidence if the ground itself is in poor condition, or if the work done by builders surrounding the property and its foundations is poor
- Decomposing organic fill: Fill dirt is used to tend to depressions or holes in the ground, but if the fill is organic it can decompose and lose structure
- Underpinning: Underpinned foundations can be found in properties that have previously experienced subsidence, which means there is a risk that it may happen again
- Old homes: Homes build in the Victorian or Edwardian eras have shallow foundations, less than the 1m minimum for UK houses today – making them more vulnerable to subsidence
What are the signs of subsidence?
There are a number of recognisable signs and symptoms of subsidence. Keep an eye out for:
- New cracks forming or existing cracks expanding
- Wallpaper rippling in patches
- Doors and windows sticking, which is caused by door and window frames warping
How do I know a crack is caused by subsidence?
If a crack is caused by subsidence, you can usually tell because:
- It’s wider than 3mm
- It appears on both inner and outer walls
- It’s narrower at the bottom
- It’s diagonal
- It’s nearby a window or door
- It gets wider over time
You might notice cracks if your home is a new build, but this is often as a result of ‘settlement’, where your home is naturally settling onto its foundations – a normal occurrence in new properties.
How can you prevent subsidence?
Subsidence can be hard to stop if it’s already occurring, but taking the following steps can reduce the risk of it happening as well as the damage it might cause:
- Ensure any trees or shrubbery are planted further than five or 10 metres away from the property
- Maintain your pipes, plumbing and drainage to prevent water leakage
- Check if there is a history of subsidence on a property before purchasing
What should I do if I have subsidence?
It’s important to contact your insurer as soon as possible if you suspect your house is subsiding. They’ll organise a survey to see for sure whether subsidence has become an issue, and if it is you can start thinking about the next steps to take.
Are there any problems related to subsidence I can claim for?
Aside from subsidence, your home insurance policy may also offer cover for:
- Heave: Heave is when the ground around and under your property becomes saturated with water, causing it to swell up and push against the structure of your home
- Landslip: Landslip is when the ground around and under your home slides down a slope
What is subsidence home insurance?
Subsidence home insurance is a policy that protects you against the cost of repairs you’ll have to make if your home experiences subsidence.
Do I need subsidence home insurance?
If your home is at risk of subsidence, then an appropriate policy can save you a lot in repair costs – for example, underpinning your home can cost as much as £15,000. Check for signs and symptoms of subsidence before you purchase a new home as it can be a deal breaker – premiums for subsidence insurance are often quite high, as is the excess fee you’ll need to pay.
What does subsidence home insurance cover?
A good subsidence insurance policy will cover you for the cost of loss and damages caused by your house subsiding. If you need to leave the property for a period of time you should also be able to claim for alternative accommodation – depending on the specifics of your policy.
However not all policies will cover you for preventative measures such as underpinning, for which you might need to go to a specialist insurer. If you live in a listed building or if your property has irregular features such as a flat roof, you may also need specialist insurance to claim for subsidence damage.
How much does subsidence home insurance cost?
You can generally expect home insurance to be more expensive when you include cover for subsidence, as it would with any other additional policies. However you should also consider the excess fee.
Why are excess fees for subsidence insurance so high?
Excess fees are what you pay towards the cost of your claim before your insurer picks up the rest – it essentially acts as a safeguard for the insurer to make sure you only claim when you really need to. These fees can be higher than usual for subsidence claims as the repair costs associated with subsidence often reach into the tens of thousands.
Compare subsidence home insurance quotes
If your home is at risk of subsidence, comparing home insurance policies with MoneySuperMarket can help you find cheaper cover for your property. All you need to do is tell us a little about yourself and your home, including when it was built, whether it’s already at risk of subsidence, and how much cover you’d like on your policy.
We’ll use this to put together a list of quotes from a range of providers, so you can compare deals by the monthly and annual cost of the policy, the level of cover you’ll get, and the excess you’ll need to pay to make a claim. Once you’ve found the deal you want, just click through to the provider to finalise your purchase.
As with all insurance policies, the cheapest available deal isn’t always the best. We recommend you aim to balance the cost with the cover you get, so you don’t end up under-insured or overpaying for a policy you don’t need.