At Lansdown Insurance Brokers, we’ve seen the impact subsidence can have on properties, with some claims reaching staggering amounts. But subsidence isn’t the only ground movement problem that can affect your property, heave and landslip are also critical issues that require attention.
The subsidence market continues to face increasing pressure as periods of prolonged hot, dry weather become more common. Extended dry spells can cause clay soils to shrink, increasing the risk of ground movement and damage to property foundations.
With temperatures regularly exceeding seasonal averages, insurers and property professionals are seeing growing concern around subsidence-related claims. These emerging “surge summers” are contributing to a longer-term trend of more frequent and potentially more severe subsidence events across parts of the UK.
Our Block of Flats Insurance and Landlord Insurance team discusses what you need to know about these ground movements, how to spot them, and what to do if your property is affected.
What is Subsidence?
Subsidence occurs when the ground beneath a property sinks, pulling the foundations down with it. This movement can cause walls and floors to shift, leading to cracks and potentially destabilising the entire structure. Various factors can cause subsidence, including clay shrinkage, tree roots, water erosion, and poor foundation work.
What is Heave?
Heave is essentially the opposite of subsidence. Instead of the ground sinking, it rises, pushing the foundations upward. This upward movement often results from the soil expanding due to excess moisture, which can happen when a large tree is removed, causing the soil to swell. Heave can lead to significant structural damage as it forces walls, floors, and foundations out of alignment.
What is Landslip?
Landslip refers to the sideways movement of the ground beneath a property, often caused by soil erosion or when a property is built on or near a slope. Unlike subsidence and heave, which involve vertical ground movement, landslip can shift the entire foundation horizontally, leading to severe structural issues.
How to spot signs of ground movement
Cracks in the Walls: Cracks can indicate subsidence, heave, or landslip. Subsidence cracks are often wider at the top, while heave-related cracks might appear wider at the bottom. Cracks from landslip can appear as diagonal fractures. Any crack wider than 3mm, visible both inside and outside the property, or located near doors and windows, should be investigated by a professional.
Changes in Doors and Windows: If your doors and windows no longer fit properly or have become difficult to open or close, this could be a sign of subsidence, heave, or landslip. These movements can distort the frame, making the fixtures misalign.
Ripples in Wallpaper: While dampness can cause wallpaper to wrinkle, subsidence, heave, or landslip can also lead to similar effects due to shifting walls.
Risks of Ignoring Subsidence, Heave, or Landslip
Ignoring these issues can lead to serious consequences, including:
Higher Insurance Premiums: Properties with these issues are more expensive to insure due to the increased risk of damage
Decreased Property Value: Properties with a history of ground movement are harder to sell and may fetch lower prices
Structural Damage: Over time, unresolved subsidence, heave, or landslip can cause extensive damage, making the property unsafe
While you can’t control every factor, there are steps you can take to reduce the risks:
- Maintain Guttering and Plumbing: Regularly check for leaks and ensure your guttering is in good condition to prevent water from saturating the soil around your property.
- Manage Trees Carefully: Avoid planting large trees near your property. If you already have trees nearby, consult a tree surgeon to manage their growth. While they can contribute to subsidence, removing them can sometimes lead to heave.
- Follow Building Regulations: Ensure any extensions or building work comply with regulations to avoid issues with foundations.
What should you do if you suspect subsidence, heave or landslip?
If you notice signs of subsidence, heave or landslip, you should contact your insurer as soon as possible to report the issue. Avoid arranging your own investigations or appointing a surveyor without first speaking to your insurer, as any costs incurred may not be recoverable if the damage is not caused by an insured risk.
Once a claim has been reported, insurers will typically appoint a specialist Subsidence Loss Adjuster to investigate the cause of the damage and determine whether cover applies under the policy.
Depending on the circumstances, investigations may include:
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Ground investigations
A ground investigation, comprising trial pits and boreholes to establish the condition of the soil supporting the foundations of the building. A specialist contractor is instructed to determine how deep the foundations are, what they rest on and whether nearby drains are leaking. Boreholes are done to obtain samples for analysis.
The results of the investigation allow the Subsidence Adjuster to build up a picture of the condition of the soil under the foundations and thus help enable a decision about the cause of damage to be made.
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Drainage surveys
A camera survey of underground drainage systems may be undertaken to identify leaks, defects or other issues that could be affecting the ground beneath the property.
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Crack monitoring
A Loss Adjuster may decide that crack monitoring is required to establish when there is any continuing movement across the cracks. The results of crack monitoring can help in determining the cause of damage and the type of repair required. Once monitoring has been established the ground investigation team will return to the property to carry out further measurements on a regular cycle. Monitoring of the cracks are done over a specific period of between 12-18 months depending on the cause of the damage, and the timing of mitigation measures.
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Level monitoring
In a small number of cases the Subsidence Adjuster may need to measure whether there is any continuing movement of the whole building by monitoring the levels of a series of points fixed to the walls around its perimeter. Level monitoring may also be needed if the mechanism of movement cannot be readily determined from the patterns of cracking alone.
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Arboricultural assessments
If trees or vegetation are suspected to be contributing to the issue, an arboricultural consultant may be instructed to assess their impact and recommend any appropriate management or removal measures.
How do I repair subsidence, heave or landslip?
Where investigations confirm the cause of the movement and policy cover has been established, the focus is usually on addressing the underlying cause to reduce the risk of further damage. This process is known as mitigation.
For example, if subsidence has been caused by shrinkable clay soils affected by nearby trees, reducing or removing the vegetation may be recommended. If leaking drains have weakened the supporting ground, repairs to the drainage system may be required.
Once the loss adjuster is satisfied that the property has stabilised, permanent repairs can be carried out. In many cases, the insurer will arrange for approved contractors to complete the remedial works, with the policyholder responsible for paying any applicable policy excess.
While underpinning is sometimes required, it is generally considered a last resort and is far less common than measures aimed at addressing the root cause of the movement.
Insuring a property with ground movement
Insurance for properties with ground issues is available, but it may come with higher premiums and/or increased excess. Make sure you provide all necessary information to your insurance provider to ensure adequate cover.
By understanding the signs and taking preventative measures, you can protect your property and avoid costly repairs. If you suspect subsidence, heave or landslip, don’t delay your insurance provider to address the problem as soon as possible.
For more information or assistance with regards to your insurance, feel free to reach out to Lansdown Insurance Brokers. We’re here to help you safeguard your property.
Frequently Asked Questions
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What does Subsidence look like?
Subsidence can appear in several ways, but the most common signs include cracks in walls, ceilings and brickwork, particularly around doors and windows. You may also notice doors and windows becoming difficult to open or close, sloping floors, or wallpaper wrinkling without an obvious cause.
It’s important to remember that not all cracks indicate subsidence. Buildings naturally move over time, and minor cracking can occur as part of normal settlement. If you’re concerned, contact your insurer or seek professional advice.
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What do Subsidence cracks look like?
Subsidence cracks are typically diagonal and wider at one end than the other. They are often found around doors, windows and extensions where structural movement is most noticeable.
In many cases, subsidence cracks are wider than 3mm and may be visible both internally and externally. Fresh cracks may also appear suddenly or continue to widen over time.
However, cracks can also be caused by heave, landslip, settlement or general wear and tear, so specialist investigation is often needed to determine the cause.
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Subsidence examples
Examples of subsidence can include:
- Diagonal cracks running through brickwork.
- Cracks extending from the corners of doors and windows.
- Doors and windows sticking or becoming misaligned.
- Gaps appearing between walls and skirting boards.
- Sloping floors or uneven surfaces.
- Extensions pulling away slightly from the main building.
The symptoms can vary depending on the type of property, the underlying soil conditions and the cause of the movement.
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Is Subsidence dangerous?
Subsidence should always be taken seriously, but it does not necessarily mean a property is unsafe to occupy.
In many cases, movement is gradual and can be managed effectively once the cause has been identified. However, if left untreated, subsidence can lead to more significant structural damage and increasingly costly repairs.
If you notice signs of subsidence, you should report the issue to your insurer promptly so that appropriate investigations can be carried out.
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How much does Subsidence devalue a property?
The impact of subsidence on a property’s value can vary significantly depending on the severity of the damage, whether the issue has been resolved, and the availability of insurance cover.
Properties with unresolved subsidence can be more difficult to sell and may achieve a lower sale price. However, where the cause has been identified, remedial work completed and the property has been monitored and certified as stable, the impact on value may be reduced.
Prospective buyers will often want reassurance that the issue has been professionally investigated and repaired, with supporting documentation available.
About Lansdown Insurance Brokers
Lansdown Insurance Brokers are specialists in Block of Flats Insurance and Landlord Insurance. We can provide flexible policies to suit individual client needs and provide advice on what cover is required. For more information call the team on 01242 524498.
Lansdown is part of the Benefact Group, a charity-owned, international family of financial services companies that gives all available profits to charity and good causes.