The Crumbling Foundations of London

London’s record-breaking heat has brought a new concern for homeowners: the literal crumbling of their properties’ foundations. This phenomenon, linked to subsidence caused by extreme heat and dry conditions, is reported across London and parts of southeast England. It’s not just a localized issue; it’s a symptom of a broader problem that highlights our precarious relationship with the climate.

The root cause is straightforward: clay-rich soil beneath homes shrinks and shifts as moisture evaporates during hot, dry periods. This “shrink-swell” process can lead to uneven ground movement, causing cracks in walls and doors that refuse to close. The type of clay found beneath much of London contains expansive minerals that respond strongly to changes in moisture.

The scale of this issue is alarming. Hot summers bring a surge in subsidence claims, with insurers paying out record amounts in recent years. In 2025, the UK insurance industry paid out $415 million in subsidence-related claims, up 10% from the previous year. This problem isn’t limited to London; as climate change takes hold, it’s spreading to other parts of the country.

The economic implications are stark. With property values already under pressure due to rising interest rates and economic uncertainty, subsidence could become a major headache for homeowners and insurers alike. One expert noted that “in the near future, subsidence might not be insured anymore.” If this happens, many property owners will face substantial repair costs or even have to sell their homes at a loss.

Our increasing reliance on insurance to mitigate climate change’s effects is also a concern. Rather than addressing the root causes of this problem, we’re simply passing the buck to insurers and taxpayers. This approach ignores the fact that our built environment is being destabilized by extreme weather events.

The British Geological Survey warns that more than 26% of properties in London could be affected by subsidence by 2070 if global warming continues at its current pace. It’s not just about property values or insurance costs; it’s about the very fabric of our cities and towns.

To address this issue, we need to take a proactive approach to mitigating subsidence risk. This means investing in research into new building materials and techniques that can withstand extreme weather conditions. We also need to rethink our relationship with climate change: rather than just trying to mitigate its effects, we should be working towards reducing carbon emissions and adapting our built environment to the new reality.

The warning signs are clear: if we don’t take action, the consequences will be catastrophic. For London’s homeowners, the stakes are already high – but for the entire country, this is a wake-up call that can’t be ignored. The crumbling foundations of our cities aren’t just a cosmetic issue; they’re a symptom of a deeper problem that requires a fundamental shift in our approach to climate change and its impact on our built environment.

As we move forward into an uncertain future, one thing is clear: the status quo is no longer tenable. We need to take bold action – and fast – to prevent the very foundations of our cities from crumbling beneath our feet.