Around a third of homes in France are now at risk of developing cracks in the walls or broken pipes underground because of the expansion and contraction of clay soil - made worse by the country's increasingly severe droughts.
More than 12 million houses in France - around a third of the total - are now built on clay soils with a medium or high risk of shrinking and swelling, which can cause serious structural damage.
The phenomenon, known in French as retrait-gonflement des argiles (RGA), happens when clay soil under a house's foundations dries out and shrinks during droughts, then swells again when the rain returns.
When this happens repeatedly over several years, the foundations of the house and the soil it's built on are weakened, causing cracks in walls and distorted doors and windows.
In the worst cases, cracks can run right through the walls and buried water pipes can break.
READ ALSO: EXPLAINED: What to do if your French home is cracking because of drought
The growing cost of repair
The 2022 drought alone cost €3.5 billion in payouts under France's natural disaster insurance scheme, according to the Ecological Transition Ministry, which puts the average cost of a residential RGA claim at €16,500.
That amount is expected to rise significantly; according to the ministry, the latest projections by the Caisse centrale de réassurance (CCR) forecast an increase of between 44 and 162 percent in RGA claims by 2050, as climate change makes droughts more frequent and more severe.
2026
Clay soil has more potential to inflict damage to property when conditions veer from very wet to very dry - which is exactly what happened in 2026. At the start of the year, France experienced its wettest February since records began in 1959, with twice the normal rainfall, according to Météo-France.
Conversely, Summer 2026 was the hottest in France since records began in 1900 - a phenomenon that would have been almost impossible without climate change, according to an assessment by Météo-France.
The summer also saw one of the most severe droughts on record, with around 60 percent of the country on 'crisis' level water restrictions. many parts of the country are still experiencing drought conditions.
READ ALSO: French water restrictions continue after record-breaking September
What's the government doing about it?
In October 2025 the government launched an experimental fonds de prévention argile (clay prevention fund) in 11 départements: Allier, Alpes-de-Haute-Provence, Dordogne, Gers, Indre, Lot-et-Garonne, Meurthe-et-Moselle, Nord, Puy-de-Dôme, Tarn and Tarn-et-Garonne.
The fund is targeted at owner-occupiers whose homes are still in good condition.
It covers a vulnerability diagnostic, to determine the extent of the risk to the person's home, as well as preventive works, such as better drainage or removing tree roots too close to the house. Grants cover between 50 and 90 percent of the cost depending on household income.
The idea is to prevent cracks from appearing, rather than repair them once they have.
But take-up has been slow. By the end of April 2026, nearly 2,000 people had completed the online eligibility check and 218 households had been found eligible, but only 19 applications had been submitted across all 11 départements, minister Mathieu Lefèvre told reporters in May.
The government subsequently loosened the rules, widening the scheme to include houses with three storeys rather than two, and increasing the maximum crack width for the works stage from 1mm to 5mm.
Check whether you are eligible for the scheme here.