Most people think of subsidence as something that happens to other houses. A crack in someone else’s wall, a survey flag on a property you didn’t end up buying. But after the run of record-hot, rain-starved seasons the UK has just lived through, the ground beneath millions of British homes is moving more than it used to, and the latest projections suggest many of those homes are in postcodes their owners would never have suspected.

Fresh research landed in June 2026, mapping where subsidence is heading over the coming decades, and it’s worth your attention. The findings are striking, and they made national headlines for good reason.[1][3] They also match what the claims data has been showing for a while. So here are the key numbers, without the alarm, and what actually matters if you own, rent, or let a home in an at-risk area. Almost all of it is worth knowing before there’s a problem, not after.

The Numbers Worth Paying Attention To

The most detailed projections yet lay out three possible futures, depending on how quickly the climate warms. On the emissions path the world is currently tracking closest to, more than 1.8 million British homes could become highly or extremely likely to suffer clay shrink-swell subsidence by 2070.

On a worse trajectory, that figure climbs past 4.2 million. Even on the optimistic path aligned with the Paris Agreement, around 500,000 properties are still likely to be affected.[1][6]

London faces the greatest exposure

When the research was published, the Guardian mapped the danger zones across London, Essex, Kent, and a corridor of eastern England stretching up towards the Wash.[3]

London faces the greatest exposure. On the central projection, the share of London homes likely to be affected passes 26% by 2070, and on the worst-case path, it could reach 54%, with more than 2.5 million properties in the city alone becoming highly or extremely likely to be affected.[1]

The northern and central boroughs, Camden, Islington and Barnet among them, carry the heaviest exposure, along with much of Kent.[1][6]

It’s already showing up in claims

This is not only a future projection. The impact is already visible in claims data today. In the first half of 2025, insurers across the industry handled £153 million in subsidence claims, supporting close to 9,000 households, with the average payout reaching £17,264.[2]

Across the full year, total property claims hit a record £6.1 billion, including £1.2 billion in weather-related damage, with domestic subsidence alone accounting for £307 million.[5]

The 2025 weather tells the rest of the story: the UK recorded its warmest and sunniest year on record,[16] its warmest summer on record,[17] and one of its driest springs in more than half a century.[1] Dry ground shrinks, foundations move with it, and the claims tend to arrive months later.

Why It Comes Down to Your Soil, Not Your County

This is the part most coverage tends to overlook. Subsidence risk doesn’t respect county lines, and it certainly doesn’t behave the same across a whole region. It’s driven by what’s directly beneath your home.

In simple terms, subsidence is the downward movement of your foundations caused by changes in the ground supporting them, and in the UK, the usual cause is shrinkable clay. When clay-rich soil dries out, it shrinks, and when it rehydrates, it swells, often unevenly across a single building.[19] That’s why one corner of a house can drop while another remains in the same position, and why the damage usually appears as cracking.

The clay belt running under London and the South East is especially prone to this because much of it is geologically young and soft, readily giving up and taking on moisture as the weather swings.

That underlying geology, combined with the bigger temperature and rainfall changes the South East is projected to see, is what makes the region such a hotspot. Two neighbouring postcodes can carry very different risk depending on their soil, their trees and the age of the buildings on top. It’s a strong argument for understanding your own ground rather than relying on a broad regional label, and it’s reflected in the way home insurance is priced across affected areas.

What Subsidence Actually Looks Like

If you want to keep an eye on your own home, it’s worth knowing the early warning signs. Chartered surveyors point to diagonal cracks near windows and doors, particularly any wider than about 3mm, along with doors and windows that start to stick, sloping floors, and rippling wallpaper.[4]

Trees do more damage than the weather

Weather is only half the story, and this often surprises people. Around 70% of subsidence cases are linked to tree roots drawing moisture out of shrinkable soil, with leaking drains and broken water mains adding to the problem.[4] A thirsty, mature tree close to your foundations on clay soil is often doing far more damage than the climate alone.

It’s also why the single most useful thing you can do is manage vegetation and keep your drainage in good repair, long before any cracks appear.

Why a diagnosis is rarely a disaster

There’s a measured point to make here, too. A diagnosis of subsidence isn’t the catastrophe it’s sometimes framed as. Surveyors note that fewer than 5% of affected homes ever require underpinning, and that, where it is required, it should be a last resort, with costs ranging from £10,000 to £75,000 for a typical house.[4]

Most cases are resolved through monitoring, drainage fixes, and root management. Understanding this matters, because informed action is far more useful than alarm.

The Costs That Arise Before Any Repair

The repair bill is only one part of the financial picture, and often not the biggest. Subsidence exposure can push up insurance premiums, dent a property’s value, and, in the worst cases, trigger engineering work, with several of those costs incurred before a single brick is touched.[1][6]

A home with a confirmed subsidence history casts a shadow over its saleability, its mortgageability, and the kind of cover available to it, which is precisely why specialist subsidence insurance exists for properties that have already been through it.

You can arrange previous subsidence cover through Frontier Insurance, provided you can supply one of two things: a Certificate of Structural Adequacy issued after an insurance claim is completed, or a chartered surveyor’s full structural (Level 3) building survey. Either must confirm the repairs were successful with no ongoing movement. A general note that works were carried out is not enough.

The type of home you own shapes the picture too. Older, period properties with shallow Victorian footings tend to sit in a higher-risk bracket than modern builds with deeper foundations, which is why listed building insurance and other cover for older homes needs particular care in clay-rich areas.

If you own a period or older property in a clay-rich area, Frontier Home Insurance offers specialist cover for listed and older homes designed around the higher ground risk these properties carry, so you’re properly protected rather than relying on a one-size-fits-all policy. The cheapest moment to deal with ground risk is always well before you ever need to make a claim.

It’s Not Just Homeowners Who Should Care

If you rent out property or live in rented housing, this is squarely your concern as well. The private rented sector comprises around 5.5 million homes in Great Britain,[7] and these tend to be older than owner-occupied stock, with 32% of privately rented homes in England built before 1919, compared with 20% of owner-occupied homes.[8]

Older properties don’t automatically subside, but they cluster in exactly the kind of housing where movement issues surface, and many sit in London and South East postcodes flagged as highest risk.

If you’re a landlord

For landlords, subsidence has become a maintenance priority; it simply wasn’t a decade ago, whether you hold a single buy-to-let under landlord insurance or run a larger portfolio. The low-cost interventions, sound gutters and drains, sensible tree management, and early attention to small cracks are also the ones that stop a minor ground issue from becoming a structural one.

The same applies if you let through short-stay platforms under Airbnb host insurance, or if your property is a park home or a static caravan, where what’s beneath the structure matters every bit as much.

Why renters feel it too

The costs don’t need to remain solely with the owner. With average UK rents reaching £1,377 a month in the year to March 2026,[9] rising premiums and repair bills ripple through the wider market. Subsidence also belongs in the same conversation as other climate-driven property risks, so it’s worth thinking about flood risk home insurance and ground movement together rather than in isolation.

The housing-quality numbers underline how stretched parts of the stock already are: in 2023, 15% of homes in England failed the Decent Homes Standard, rising to 21% among privately rented homes.[10]

How to Check Your Own Area and Stay Ahead of It

You don’t need to wait for a survey to get a feel for your local ground risk. There are free public map tools that let anyone explore the geology beneath their area, including the BGS Geology Viewer and the BGS GeoIndex, both of which are a sensible first step if you’re buying, renting, or just want to understand your own home better.[11][12]

Simple habits that protect your home

Beyond that, protecting a home in a clay area mostly comes down to a few sensible habits: take specialist advice before major building work, avoid planting large, thirsty trees close to the house, keep drains and pipes well-maintained so they aren’t feeding moisture into the ground, and act on early warning signs rather than waiting to see if they worsen.[4][13]

If you’re buying in southern England, it’s worth asking informed questions before you commit, too: what’s the soil class, how close are the mature trees, how old are the foundations likely to be, and has the area seen subsidence activity recently? None of these are difficult to ask, and asking them early is far better than learning the answers after completion.

Where This Leaves You

Flooding and storms still dominate the climate-and-property headlines, and understandably so, because they’re dramatic and easy to picture. Subsidence is the quiet risk. It moves slowly, often out of sight, and the damage surfaces long after the dry spell that triggered it. That lag is a major reason the public conversation has trailed behind reality, even though the evidence clearly points to subsidence being a bigger issue in England than elsewhere in the UK, with the South East most exposed.[14][15]

The latest research changes the calculation. A record-hot, dry year, £153 million in subsidence claims in just six months, and projections putting more than half of London’s homes in elevated-risk territory by 2070, all point the same way.[1][2] This is starting to look less like a run of bad luck and more like a new normal, which is exactly why bodies like the Climate Change Committee keep stressing that climate risks need to stay insurable to keep the housing market functioning.[18]

The honest takeaway is straightforward. Subsidence has become concentrated enough, costly enough, and clearly enough linked to a warming climate that it deserves the same attention you’d give flood risk when you assess a home. You can’t change the geology under your postcode, but you can understand it, plan around it, and make sure your cover actually fits the property you own.

If you’d like to check yours or get a quote, you can do it directly with Frontier Insurance. The most valuable work always happens before the first crack shows.

References

[1] British Geological Survey (2026) Latest research emphasises climate-related subsidence risk to millions of British homes. Available at: https://www.bgs.ac.uk/news/latest-research-emphasises-climate-related-subsidence-risk-to-millions-of-british-homes/

[2] Association of British Insurers (2025) Insurance support tops £150 million for homes affected by subsidence. Available at: https://www.abi.org.uk/news/news-articles/2025/7/insurance-support-tops-150-million-for-homes-affected-by-subsidence/

[3] The Guardian (2026) Millions of homes in London, Essex and Kent sinking amid climate crisis, data shows. Available at: https://www.theguardian.com/environment/2026/jun/11/millions-homes-london-essex-and-kent-sinking-climate-crisis-subsidence

[4] Royal Institution of Chartered Surveyors (2022) Subsidence. Available at: https://www.rics.org/consumer-guides/subsidence

[5] Association of British Insurers (2026) Adverse weather pushes property insurance payouts to £6.1 billion in 2025. Available at: https://www.abi.org.uk/news/news-articles/2026/2/adverse-weatherpushesproperty-insurance-payouts-to-6.1-billionin-2025/

[6] Geographical (2026) Millions of UK homes under threat of sinking due to climate change, study finds. Available at: https://geographical.co.uk/news/millions-of-uk-homes-under-threat-of-sinking-due-to-climate-change-study-finds

[7] Office for National Statistics (2025) Private rented sector statistics from across the UK: 2025. Available at: https://www.ons.gov.uk/peoplepopulationandcommunity/housing/articles/privaterentedsectorstatisticsfromacrosstheuk/2025

[8] Ministry of Housing, Communities and Local Government (2025) Chapter 1: Profile of households and dwellings. Available at: https://www.gov.uk/government/statistics/chapters-for-english-housing-survey-2024-to-2025-headline-findings-on-demographics-and-household-resilience/chapter-1-profile-of-households-and-dwellings

[9] Office for National Statistics (2026) Private rent and house prices, UK: April 2026. Available at: https://www.ons.gov.uk/economy/inflationandpriceindices/bulletins/privaterentandhousepricesuk/april2026
[10] Ministry of Housing, Communities and Local Government (2025) English Housing Survey 2023 to 2024: drivers and impacts of housing quality. Available at: https://www.gov.uk/government/statistics/english-housing-survey-2023-to-2024-drivers-and-impacts-of-housing-quality/english-housing-survey-2023-to-2024-drivers-and-impacts-of-housing-quality

[11] British Geological Survey (n.d.) BGS Geology Viewer. Available at: https://www.bgs.ac.uk/map-viewers/bgs-geology-viewer/

[12] British Geological Survey (n.d.) GeoIndex (onshore). Available at: https://mapapps2.bgs.ac.uk/geoindex/home.html

[13] British Geological Survey (2021) Six ways to prepare your home for climate change related subsidence. Available at: https://www.bgs.ac.uk/news/six-ways-to-prepare-your-home-for-climate-change-related-subsidence/

[14] UK Climate Risk (2021) Summary for England (CCRA3-IA). Available at: https://www.ukclimaterisk.org/publications/summary-for-england-ccra3-ia/

[15] UK Climate Risk (2021) Housing. Available at: https://www.ukclimaterisk.org/wp-content/uploads/2021/06/CCRA3-Briefing-Housing.pdf

[16] Met Office (2026) 2025 is double-record breaker: UK’s warmest and sunniest year on record. Available at: https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2026/2025-is-double-record-breaker-uks-warmest-and-sunniest-year-on-record

[17] Met Office (2025) Summer 2025 is the warmest on record for the UK. Available at: https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2025/summer-2025-is-the-warmest-on-record-for-the-uk

[18] Climate Change Committee (2026) A well-adapted UK. Available at: https://www.theccc.org.uk/publication/a-well-adapted-uk/

[19] British Geological Survey (n.d.) Swelling and shrinking soils. Available at: https://www.bgs.ac.uk/geology-projects/shallow-geohazards/clay-shrink-swell/