Millions of UK Homes Face Rising Subsidence Risk

Subsidence has always been a concern for homeowners on certain soils, but new data suggests the problem is set to get much worse. The British Geological Survey’s June 2026 GeoClimate dataset projects that over 1.8 million UK properties will be highly or extremely susceptible to clay shrink-swell by 2070 under a medium emissions scenario.

Under higher emissions, that figure rises to 4.2 million. Even under the most optimistic scenario, aligned to the Paris Agreement, around 500,000 properties could still be affected.

Which Parts of the UK Are Most at Risk?

Clay shrink-swell is the main driver behind the projected increase. Clay soils expand when wet and contract when dry, and as climate change brings hotter, drier summers, those cycles are becoming more extreme and more frequent. In 2025, the UK experienced its warmest spring on record and its driest in more than 50 years. Subsidence-related insurance claims in the first half of that year alone totalled £153 million.

The BGS data points to London as one of the highest-risk areas in the country. Boroughs including Camden, Islington and Barnet sit on thick deposits of London Clay, which is particularly reactive to moisture change. Large parts of Kent are also flagged as high-risk, with the underlying geology making homes there especially vulnerable to ground movement during prolonged dry spells.

It’s worth noting that these aren’t areas with marginal risk. The BGS categorises them as highly or extremely susceptible, meaning the ground conditions are already problematic, and climate change is making them worse.

Why Hotter Summers Make Things Worse

The link between climate change and subsidence risk is direct. As summers become drier, clay soils lose moisture and shrink. That shrinkage pulls the ground away from foundations, and if the movement is uneven, cracks appear in walls, around door frames and window openings.

This isn’t a distant threat. The UK has already seen a run of unusually dry summers, and the BGS projections are built on the assumption that this trend will continue. Properties that have been perfectly stable for decades could begin to show signs of movement as conditions shift.

The problem is also cumulative. Each dry summer puts further stress on foundations, and if that stress builds up over several years without any intervention, the damage becomes harder and more expensive to fix.

What Subsidence Actually Costs

The financial consequences are significant. The average subsidence insurance payout in 2025 exceeded £17,000, and industry estimates suggest total subsidence-related costs across the UK could reach £1.9 billion annually by 2030.

Those figures reflect both the cost of structural repairs and the disruption involved. Subsidence claims are rarely simple. They often require specialist surveys, underpinning work and extended periods of monitoring before a property is considered stable again.

Tailored Subsidence Insurance Becomes Vital for Some Homeowners

For homeowners without adequate cover, the out-of-pocket costs can be far higher. In serious cases, properties have been left uninsurable on the standard market after a subsidence event, leaving owners in a difficult position when it comes to selling or remortgaging.

Tailored subsidence insurance exists for exactly these situations. Unlike a standard policy, it’s built to account for a property’s history and the ground conditions it sits on, covering subsidence, heave and landslip under a single policy. Under these policies, each property is assessed individually, which matters when standard insurers are reluctant to quote at all. That’s why this type of insurance is becoming something homeowners in at-risk areas can no longer ignore.

What Homeowners in High-Risk Areas Should Do Now

If you own a property in one of the areas highlighted by the BGS data, it’s worth taking the risk seriously before any movement occurs. A few practical steps to consider:

• Get a soil survey or check existing reports to understand the ground conditions beneath your property.
• Be aware of large trees close to the foundations, as their roots draw moisture from clay soils and accelerate shrinkage.
• Monitor any existing cracks in walls or around windows and doors, noting whether they change size or shape over time.
• Fix leaking drains or pipes promptly, as water leaching into clay soil can cause it to swell unevenly and shift foundations.
• Check your home insurance policy carefully. As mentioned above, standard cover often falls short when it comes to subsidence, particularly for properties in high-risk zones or those with any history of ground movement.

Act Before the Ground Shifts

The BGS projections are a warning worth heeding. With millions of properties set to move into higher risk categories over the coming decades, the time to check your exposure is now, not after cracks appear in the walls.

Understanding your soil type, keeping an eye on any structural changes and making sure your insurance reflects the actual risk are all steps that could save significant money and stress down the line. The risk isn’t going away, and for homeowners in the most vulnerable areas, getting ahead of it is far cheaper than dealing with the consequences later.