Will 2025 be a bad year for subsidence claims?

It will come as no surprise that hot dry summers are directly linked to an increase in the number of subsidence claims. A sudden increase in subsidence issues is often called a “surge year” for insurers and here we look at what 2025 will bring in terms of subsidence and the home insurance market.

What factors increase the risk of subsidence?

Whilst there are different causes, subsidence seen during a surge year is often the result of the ground losing moisture. During dry periods, soil (particularly clay-based soil) can shrink, and when this occurs beneath a property, the shrinking soil can cause the foundations to drop, which in turn can cause cracking. Trees in the area can cause or exacerbate this with roots taking up moisture and drying out the soil.

Subsidence is more likely to occur when we have a wet period followed by a prolonged dry period. (7). With global warming bringing hotter & drier summers, and warmer & wetter winters, subsidence cases are expected to rise – with over 1 million more homes estimated to be at risk of subsidence by 2050 (2).

The heatwaves in 2003 & 2006 both led to peaks in subsidence claims (4), with further surge years in 2018 (warmest summer since 2006 and driest since 2003) and 2022 (a new UK temperature record) (1). The surge of subsidence claims in 2022 happened in the second half of the year with 18,000 claims in 6 months, compared to just 5,000 claims in the first half of the year (1).

2025 saw the driest spring for 100 years (1), so there is a potential for a surge of subsidence later this year.
Is my home at risk of subsidence?

There are many factors to consider. These include:

Clay soils: Clay or clay rich soil is especially vulnerable to weather changes (3). During wet weather, clay rich soil absorbs larger amounts of water, causing the soils to swell, being heavy and dense with moisture. When clay rich soils dry out, the soil becomes very hard and shrinks. This is known as ‘shrink-swell’ (4). This means that there are certain areas of the UK where subsidence is a higher risk. ‘London Clay’ for example, puts areas of the southeast and London at higher risk, especially when near large trees or where the clay is nearer to the surface (5).

Because of this, if you live in a higher risk area, you might see terms such as tree maintenance conditions, an increased subsidence excess, a request for a subsidence questionnaire to be completed or even a subsidence exclusion.

Property Age: Shallow foundations can also affect the extent to which a property is affected by changing ground moisture. This means that older properties are at higher risk; with average foundations on properties built before 1920 being less than 45cm, whereas properties built after 1976 are 1m+ deep (5).

Location: Insurers use a postcode database of soils, past claims and future risk potential to underwrite policies, being more cautious depending on the data they have. The terms an insurer will apply will reflect this as will any the risk details you provide.

Subsidence claims

Since subsidence cover was added to policies in the 1970’s, the number of subsidence claims has been relatively low compared to other types of claims (around 3-4% of claims (1)), but over the last 5 years the average cost of a subsidence claim has increased (8). In 2022, during the surge of subsidence claims, the average claim cost was £10,000 per claim (1). Now, the average claim is just over £13,000 per claim (8).

Generally, a claim involving underpinning makes a claim 4-5 times more expensive (8), but with a shift in preference to keep trees, tree preservation orders, or trees belonging to local authorities, there has been an increase in subsidence claim costs.

Aside from removing vegetation & underpinning, a property can also be stabilised by other methods, including repairing leaking drains or adding additional strengthening like helix joints (stainless steel reinforcing bar).

Subsidence insurance

Obtaining home insurance for a property that has previously been affected by subsidence can be difficult.

Many insurers will simply say no, without asking for any more information, even if the movement was in the 19th century or before earlier and if it isn’t getting worse.

If you’re looking for subsidence insurance here’s some advice.

• If you’re getting home insurance quotes online, be careful before you tick any boxes. The “previous movement” statement may be amongst many others you’re agreeing to. If you agree that your home has not “been affected by any structural movement” and it has, no matter how long ago, you could be invalidating your policy.
• If you’re thinking of buying a property with a history of movement, ask for a Certificate of Structural Adequacy or a Structural Engineer’s Report which shows that the cause of the movement has been removed, that any cracks have been properly filled, and that the superstructure is now sound.
• Speak to a specialist broker like Howden. We understand the challenges of subsidence and historic movement and can negotiate with insurers on your behalf.
  To speak to us about your home insurance call 020 8256 4901 or email privateclients@howdeninsurance.co.uk

References

1. Innovation Group - Technical Bulletin - May 2025
2. The CII - Predicting and preparing for the increasing risk of subsidence
3. ABI - Subsidence | ABI
4. British Geological S Swelling and shrinking soils - British Geological Survey
5. Subsidence risks for properties in London - Structural Engineers Report
6. Subsidence 'surge years' create waves of major insurance claims, reveals IStructE guide
7. Subsidence and Trees - Woodland Trust - Woodland Trust
8. Innovation Group - Technical Bulletin – February 2025