More and more soil is being impacted by drought. Clay soils in particular are affected by drought. These soils expand and contract depending on their water content and often crack when dry. Building on them can be risky and requires a particular structural design.
Home owners in parts of France have already been impacted by recent dry spells. Roughly half of France is at risk of the effects of droughts on clay soil and 10 million homes have already suffered important damage. For example, 44% of the Loire Valley is at medium or high risk of drought-based soil movement. Large parts Italy, Spain and the UK are also at risk.
Switzerland also has areas with clay-based soils. For example, much of the city of Yverdon-les-Bains is built on clay and much of the soil around Lake Neuchâtel is at risk, reported RTS.
One advantage Switzerland has is lakes. These make it harder for the ground to dry out. Its strict building codes are also helpful. Soil testing is strict and the design of structures too. For example, a deeper foundation is preferable. However, risks remain. When the water table drops by a metre in Yverdon-les-Bains the ground moves, according to local experts.
To reduce the risks Switzerland and Europe are reviewing building codes. The resulting updated standards are likely to come into force in 2026.