The shrinkage-swelling of clay soils, or the shrink-swell phenomenon, consists of a series of movements caused by variations in the water content of clay soils. Known in France for more than 30 years, it has damaging consequences for housing that give rise to compensation, included since 1989 in the natural disaster regime, known as “Cat Nat”. This phenomenon has attracted recent attention from the public authorities due to the growing magnitude of the risk and the related claims and also because of the increase in dissatisfaction expressed by the exposed populations. Referred to by the National Assembly Public Policy Evaluation and Audit Committee concerning the prevention and compensation of damage caused by the shrink-swell phenomenon, the Court of Accounts conducted an investigation taking into account the history of the issue and above all, more recent parliamentary and administrative work. The report that is being published today shows that as the phenomenon is evolving, its management is increasingly being called into question. In view of this situation, the Court recommends promoting preventive measures and reconsidering the compensation regime.
