Are you considering buying a house with subsidence? Or perhaps you’re hoping to sell your property and are worried about some cracks that have begun to appear. Subsidence is a scary word for any homeowner or prospective buyer, but it is estimated that around 40,000 properties are affected by subsidence each year.
In this guide, we’ll explore some of the key signs of structural movement or subsidence, discuss the implications of buying or selling a property with movement, and help you decide on your next steps.
Subsidence is the downward movement or collapse of the ground that a property sits on.
All properties will experience a small amount of movement, which will largely go unnoticed. Sometimes, however, that movement occurs in a downward direction and causes the property to become unstable. When this happens, it is important to take action to protect the property from extensive damage.
Should I buy a house with structural movement?
If you’re considering buying a house with subsidence, your first step should be to gather more information. If the problem is a historic one that has been treated, it’s important to gather all of the paperwork you can from the seller. It is also advisable to ensure you have a thorough structural survey carried out before proceeding with a purchase. If subsidence may be a current issue at the property, a structural survey will assess the severity of the issue. It can also advise on work required to address the problem.
Properties with current subsidence will be unmortgageable. If you were planning to use a mortgage to purchase the property, it’s unlikely that you’ll be able to proceed. Properties with a history of subsidence are often challenging to mortgage and insure, but as long as the issue is resolved it should be possible. The Subsidence Claims Advisory Bureau (SCAB)specialises in assisting people who live in or are considering buying properties that have suffered from subsidence. They can help with securing mortgage lending and comprehensive insurance. They can also offer advice on many other aspects of owning a house with a history of subsidence.
What’s the difference between subsidence and settlement?
Most properties will experience some degree of settlement when they are first built. Settlement is caused by the ground beneath the property compacting under the weight of the new structure.
Unlike settlement, subsidence is not caused by the weight of the building. It is, instead, created by the ground beneath the property becoming unstable. Subsidence would have occurred whether the property was on the land or not.
Properties can also experience ‘heave’, which is where the ground beneath the property swells and moves in the upwards motion.
Is subsidence dangerous?
Subsidence can destabilise the structure of your home and, as a result, can be very dangerous. If you spot any signs of subsidence in your home, it’s important to investigate as a matter of urgency.
Signs of subsidence in a house
Early signs of subsidence may include torn wallpaper or windows and doors that are starting to stick. The most obvious sign of well-established subsidence, however, is the appearance of substantial cracks in your walls. When the ground beneath your property becomes unstable, it will take some of your property’s foundations with it. As one section of your property begins to move, it will put pressure on the structure of your home. Cracks will then begin to show at the point of tension.
It is important to note, however, that cracks are not always a sign of subsidence. Small hairline cracks that appear seasonally are likely to be due to the expansion or contraction of materials caused by changing weather, which is not something to be overly concerned about. Cracks that are a result of subsidence will usually be large (thicker than 2mm) and visible internally and externally. You would also expect any cracks caused by subsidence to be wider at one end and often diagonal in direction.
What causes subsidence? Subsidence warning signs to look out for
There are several things that can put a property at increased risk of subsidence. These include:
Large trees close to properties can cause problems with the stability of the property’s foundations. Large tree roots can disturb the soil beneath the foundations and thirsty plants can dry out the ground, leaving it more vulnerable to cracking and movement.
Older properties tend to have shallower foundations, which may leave them more susceptible to erosion and subsidence
It is estimated that around 80% of subsidence claims involve clay soil. Clay soil is particularly prone to cracking, shrinking and moving during warmer, drier weather. This then unsettles property foundations and causes subsidence. A good way to assess whether clay soil is likely to cause a problem is to look closely at surrounding properties for any signs of external cracks.
Any damaged water mains or household drains can create an added subsidence risk over time. Soil that becomes saturated with water can easily become unstable and erode under the weight of a property.
Any area that has a history of mining has an increased risk of experiencing subsidence. It is important to gather information about any historic mining activity as part of your pre-purchase property searches so that you can take any necessary steps if the property is at risk.
How do surveyors check for subsidence?
Surveyors will look for any signs of subsidence. This will include any subsidence cracks in walls or difficulty opening and closing doors and windows. An experienced surveyor will be able to advise you whether they believe these things to be a sign of something serious or just usual seasonal property movement.
If they do find any evidence of subsidence, your surveyor will be able to advise you on appropriate steps for further investigation and remedial action.
How much does it cost to fix subsidence?
How much it costs to fix subsidence will depend on the cause of the problem. Minor subsidence may be addressed relatively cheaply if things haven’t progressed too far. Full underpinning will cost in the region of £1,500 – £2,600 per square metre.
What is underpinning?
Underpinning a house is the process of strengthening foundations that have been affected by subsidence.
Underpinning costs will vary depending on the severity of the subsidence and the method of underpinning required to resolve the issue.
There are several different types of underpinning, including:
Mass concrete underpinning is a way of extending or deepening existing foundations and is the most common method of property underpinning. Areas of ground beneath the existing foundations will be excavated and then filled with concrete. This process is completed in small, manageable sections to ensure the property remains well supported while the work is carried out.
Piling is seen as the most versatile method of strengthening a property’s foundations. Piles are driven into the ground, bypassing the weaker, looser soil, to sit on more stable soil or bedrock below.
Jet grouting can be used to strengthen weak soil beneath the existing property foundations. High-pressure jets are used to mix existing soil with a self-hardening grout, creating a strong, substantial base to support the property’s foundations.
Underpinning used to be routine when resolving subsidence issues, but now tends to be used as a last resort for more severe subsidence. Buying an underpinned house should offer reassurance that any previous subsidence issue has been resolved. In fact, an underpinned house is usually substantially more robust and stable than a property that has never experienced any issues with subsidence.
How much does subsidence devalue a property?
How much subsidence devalues a property will depend on how severe and recent the problem is. A property that has previously been underpinned to address an issue with subsidence is estimated to be worth around 20 percent less than a similar property without any history of subsidence.
What can you do if your house has subsidence?
If you suspect subsidence, your first step should be to contact a chartered surveyor to assess the severity of the problem. Unfortunately, this is not always a quick process as any cracks or movement may need to be measured and monitored for a number of months. If subsidence is confirmed, the cause will need to be identified and addressed.
Selling a house with historical subsidence
If your property has a history of house subsidence that has been dealt with effectively, it’s important that you keep any relevant paperwork and make it readily available to any prospective buyers.
If you’ve experienced subsidence, insurance and mortgages can be more challenging to secure. This will undoubtedly put some buyers off. If you bought a house with subsidence history yourself, you’ll be aware of the challenges. This means you may be able to reassure any prospective buyers. Be open and forthcoming with information about the issue and how it has been dealt with.
Unfortunately, even if the subsidence has been dealt with and no longer poses any problem, there are some prospective buyers that will still be nervous about moving ahead with purchasing the property. It’s important to be upfront about the historic problem and how it has been resolved, as subsidence – even historic – is something that will show up in a property survey.
Subsidence FAQs
Yes, most home insurance policies should cover your property for subsidence. If your property has a history of subsidence, there may be tailored clauses in your insurance policy relating to the extent to which any further subsidence will be covered.
It’s important that you read any insurance policy carefully to ensure you’re familiar with what it does and does not cover you for.
Yes, you are legally obliged to disclose any current or historic subsidence when selling a property.
You should be honest with your estate agent from the start about any subsidence. Details should also be disclosed in the TA6 property information form as part of the conveyancing process.
If you fail to disclose details of any current or historic subsidence, your buyer could take legal action against you.
Yes, subsidence can make it harder to get a mortgage. If the property is currently experiencing subsidence, you’ll be unlikely to be able to get a mortgage. If the subsidence has been treated and there is paperwork to evidence the treatment, and there are no signs of current subsidence, you should be able to get a mortgage; however, your choice of lender and mortgage product may be more limited.
Yes, it is possible to sell a house with subsidence, though if the subsidence is current, you will likely only be able to sell to a cash buyer, as the property is unlikely to be mortgageable. If the subsidence is historic, you may be able to sell to a buyer who requires a mortgage, but it’s important to be honest with your estate agent, buyer and conveyancer. Provide any paperwork you have relating to the detection and treatment of the subsidence early in the sale process to avoid any unnecessary hold-ups.
Yes, you can insure a house that has had subsidence, but you may need a tailored insurance policy. The insurance company will need thorough information about the subsidence and when it was rectified before being able to put together a policy for you. Properties with a history of subsidence are likely to be more challenging and more expensive to insure than other properties.
A history of subsidence is something that will always need to be declared to an insurance company. As time goes on, the historic subsidence may have less of an impact on your insurance, but it’s likely that your property will always be considered ‘higher risk’.
Data predicts that around 3% of UK properties could be affected by subsidence by 2030, with that projection rising to 11% by 2070.
It’s unlikely that subsidence will stop on its own. The only exception to this might be if the subsidence has been caused by a one-off event like a burst water pipe.
It can be tempting to bury your head in the sand and ignore the early signs of subsidence, but it’s important to take it seriously and act quickly. The quicker you can address the cause of the subsidence, the better you’ll be able to limit damage to your property.
As long as the subsidence is no longer active and the cause has been addressed, you should be able to get a mortgage on a house with historical subsidence. Your property will be considered ‘higher risk’, so your choice of mortgage lender and product may be more limited, but a good broker should be able to help you find an appropriate mortgage.
You can’t get subsidence indemnity insurance, but subsidence should be covered by home insurance policies. If your property has a history of subsidence, you’re likely to need a tailored insurance policy, so it’s important to give the insurance company as much information as possible to ensure the policy they provide is suitable for your needs.
Yes, a National House Building Council (NHBC) warranty will cover any subsidence at the property during the first 10 years after the property is built. After that time, you would need to make a claim on your home insurance.
A surveyor will be on the lookout for any signs of subsidence, including any cracks or sticking doors and windows. If they have any concerns, they are likely to recommend a further survey by a structural engineer.
The cost of a structural survey (which will look specifically for signs of subsidence and the cause) will vary depending on your location, the size of your property, and how much investigation is required. Structural engineers usually charge between £90 and £200 per hour. You can expect a structural survey to cost somewhere between £175 and £2,000.
You will always have to declare a history of subsidence to your insurance company. Not doing so would likely render your insurance policy invalid.
Subsidence cracks will often first appear around doors and windows. If your home has been added to over the years, subsidence cracks may also appear where older parts of the property meet newer parts.
Subsidence cracks will often appear in a diagonal direction and may be wider at one end.
Signs of subsidence can appear quickly or become more visible over an extended period of time. This will largely depend on what’s causing the subsidence.
No, underpinning is a last resort. Whether or not your property needs underpinning is likely to depend on the root cause of the subsidence and how much the ground beneath your house has deteriorated. A structural engineer will be able to provide you with advice specific to your property.
If you live in a leasehold property, the freeholder is likely to be responsible for addressing any subsidence at the property.
Yes, you can get subsidence in mid-terrace properties. If you suspect you may have subsidence, you might want to check for some of the most common causes, such as large trees nearby, faulty or leaking drainage, and movement where the original property meets any newer extensions. If you’re in any doubt, a structural engineer will be able to advise you.
Neither is better or worse – they are both movement of the ground beneath your property. Heave means the ground is moving in an upward motion, subsidence means it’s moving in a downward motion. Both can make your property unstable and unsafe.
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