What is happening to the UK’s climate patterns? 

UK weather is becoming increasingly unpredictable, thanks to intense rainfall periods which are often followed by prolonged dry spells. This consistent cycle puts buildings under increasing pressure, especially in areas with clay-rich soils. Frequent heatwaves are contributing to significant moisture loss in soils across large parts of the country. This, coupled with sudden heavy downpours, which rapidly rehydrates the ground, increases the risk of ground instability beneath buildings and infrastructure. 

The subsidence problem 

In the UK, clay soils are particularly vulnerable to subsidence because they expand when wet and shrink when dry. Extended periods of heat and drought intensify the problem, especially where trees and large shrubs extract additional moisture from the soil through their root systems. This can potentially lead to significant ground movement beneath buildings. 

Ageing housing stock can worsen the problem. Most of UK homes built before 1976 were constructed on shallow foundations and were not designed to withstand the increasingly unpredictable moisture cycles of today. This presents a growing challenge for insurers. 

Subsidence surge events: is there more to come? 

Research carried out by insurance specialists Innovation Group earlier this year, uncovered three major subsidence surge events in 2018, 2022 and 2025, all of which were linked to periods of extreme and prolonged weather conditions (extended droughts and intense, heavy rain following these heatwaves.) Although the triggers vary, clay-rich soils are becoming increasingly vulnerable to extreme climate conditions, particularly beneath ageing housing stock. 

These events signal a rising concern about subsidence occurrence. All three events happened in the last ten years, indicating that subsidence isn’t an isolated or even a seasonal issue, but is part of the wider environmental trend influenced by climate change. As climate instability continues, we can expect more subsidence surge events in the future.  

What does this all mean for insurers?  

These events can have a significant impact on insurance companies. Actuarial models built on historical claims data are not designed to account for the clustering of surge events we’re currently experiencing. That means, as weather extremes become more common, insurers need to reassess their traditional forecasting models and pricing structures.  

Insurers with an extensive portfolio across Southern and Eastern England in particular, can find themselves overwhelmed during these surge events. Shrink-swell clay soils dominate this region of the UK, which means many insurers could potentially have numerous high-volume claims arriving simultaneously when the dry, hot weather arrives. 

Additionally, the process of subsidence claims themselves can be extremely complex. A combination of long settlement timelines, high handling costs and difficult causation disputes results in each surge event carrying claims that lasts long after the initial weather event that triggered it.  

How insurers can help homeowners mitigate risk 

Homeowners can take practical measures to reduce the risk of ground movement structural damage to their property including managing tree and vegetation in their gardens, maintaining effective drainage and ensuring soil moisture levels are consistent. Insurers can support these preventative measures by encouraging a proactive approach and enlisting the help of ground engineering experts.

Working with ground specialists such as Mainmark can help improve claim outcomes and allow for faster assessments. Ground engineering experts can provide independent assessments and technical evidence, which identifies the extent of the problem and recommends the best targeted repairs. This reduces long-term claims costs, benefitting both insurers and homeowners. 

What’s next for insurers?  

In short, evidence is beginning to emerge that subsidence is not just a result of isolated or seasonal weather events. Three significant subsidence surge events in the last 10 years strongly indicates that climate change is a key player in ground movement-related claims.  

As a result, insurers will need to reassess their underwriting models, improve early intervention strategies and work closely with ground engineering specialists such as Mainmark. This collaborative approach will help insurers and the property sector create long-term resilience. 

For more information on how Mainmark can support insurers, visit our insurance page.