Cracks after a dry summer in Fréjus or Saint-Raphaël: what should you do?
Fréjus and Saint-Raphaël combine two risk factors for residential buildings: sensitive clay soils originating from Permian formations, present across much of the Estérel massif and its foothills, and a series of marked drought episodes between 2022 and 2026. If your house has developed new cracks after a dry summer, or if older cracks have reopened, this is most likely a case of clay shrink-swell subsidence (known in France as RGA, retrait-gonflement des argiles). An RGA assessment identifies the cause of the damage, checks that your file complies with the natural disaster (« catastrophe naturelle ») order, and gathers the evidence needed for your insurance claim. Cassini Expertise, an independent firm based in Antibes, works across the entire Estérel area, from Fréjus to Saint-Raphaël and the surrounding communes.
Why this area is particularly exposed to clay shrink-swell subsidence
Several local features explain why Fréjus and Saint-Raphaël are especially sensitive to RGA.
Clay soils from the Permo-Triassic period
The subsoil of the Argens plain and the outlying areas of Fréjus partly rests on clay and clay-marl formations from the Permo-Triassic period, known for their strong capacity to shrink during dry periods and swell during wet ones. This cyclical behaviour places repeated stress on foundations, particularly when moisture variation is not uniform beneath the entire structure.
Vegetation close to foundations
Pine trees and other species with high evapotranspiration, common in gardens across the region, worsen localised soil drying when planted close to foundations. Their roots draw water from the soil several metres deep, intensifying clay shrinkage under only part of the building, which promotes differential settlement.
A housing stock largely built in the 1970s-1980s
A significant share of Fréjus and Saint-Raphaël’s residential buildings date from this period, with shallow foundations poorly suited, or not suited at all, to the nature of the soil. These properties, built before preliminary geotechnical surveys became standard practice, are statistically more exposed to RGA-related damage than recent constructions, which are now subject to mandatory soil studies.
The Estérel foothills: a tricky rock-clay interface
On the hillsides and foothills of the Estérel, the alternation between volcanic rock and pockets of clay creates transition zones where soil behaviour is uneven across a single plot. This heterogeneity promotes differential settlement, a frequent source of diagonal cracking at building corners.
Recognising clay shrink-swell subsidence damage
Certain signs should alert homeowners and justify an expert assessment:
- Diagonal or stepped cracks, following masonry joints, generally wider at the top than at the bottom.
- Separation between two parts of a building, for example at the junction of an extension, an attached garage, or an added closet, often referred to as a Hess-type separation.
- Doors and windows that stick or no longer close properly, a sign that the frame has deformed due to structural movement.
- Cracks on interior partition walls that change with the seasons: they open up at the end of summer and tend to partially close in autumn and winter as moisture returns to the soil.
This seasonal variation is a telltale sign of RGA, distinct from ordinary foundation settlement or timber-frame related damage, which typically evolves more steadily over time.
The natural disaster procedure: steps to follow
Compensation for RGA-related damage follows a strictly regulated procedure, and missing the deadlines can jeopardise your claim.
1. Check that the municipal order has been published
Compensation under the natural disaster guarantee requires the publication of an inter-ministerial order recognising the state of natural disaster for drought in the relevant commune, in the Official Journal (Journal officiel). Fréjus and Saint-Raphaël have been covered by several drought-related orders in recent years; for each period of cracking observed, it is essential to check whether an order actually covers the relevant commune and year.
2. Report the damage within the deadline
The claim must be sent to your insurer within 5 working days of the order’s publication in the Official Journal — not from the date the cracks were discovered. A dated photographic record and a precise description of the damage should accompany this declaration.
3. The assessment carried out by the insurer
The insurer appoints an expert to assess the damage. This expert primarily represents the interests of the insurance company that hired them. We recommend being accompanied by an independent expert to verify that the cause identified (RGA, rather than a construction defect or lack of maintenance, both excluded from cover) and the proposed costing accurately reflect the actual damage.
4. Compile a compliant RGA report
A complete RGA report includes a precise description of the damage, a history of weather conditions (surface soil moisture index over the relevant period), and, where warranted, a recommendation for a G2-type soil study to characterise the ground and guide foundation remediation work. For more on the full procedure applicable in the Alpes-Maritimes and the Var, see our dedicated page on RGA and natural disaster assessment in the 06 and 83.
What Cassini Expertise measures on site
A rigorous RGA assessment relies on objective measurements, essential for supporting a compensation claim or challenging an evaluation deemed insufficient.
- Installing crack gauges on active cracks, to track their width and progression over time, particularly between dry and wet periods.
- Levelling survey of the structure, to quantify any differential settlement between various points of the building.
- Analysis of available photographic history, to date the appearance or worsening of the damage and correlate it with recognised drought periods.
- Determining the cause of the damage: clay shrink-swell subsidence, foundation settlement from another cause, or damage linked to earlier underpinning work. This determination is critical, since only a recognised RGA cause, covered by an official order, opens entitlement to the natural disaster guarantee.
This measurement and diagnostic work provides essential technical evidence, whether to support an initial claim, respond to an insurance expert’s report, or pursue a counter-assessment.
Frequently asked questions
Does the natural disaster deductible always apply?
Yes. For damage linked to soil drought-rehydration recognised as a natural disaster, a specific statutory deductible of 380 euros applies, separate from the standard deductible under your home insurance policy. This amount is set by regulation and does not depend on the insurer.
My cracks close up in winter — does that mean there’s no problem?
No. Partial closing of cracks during wet periods is, on the contrary, a characteristic sign of RGA and does not mean the issue is resolved. It is important to document this seasonal pattern with regular measurements rather than assuming the phenomenon has settled.
My insurer’s expert is proposing a cosmetic repair — is that enough?
Not necessarily. If the structural cause of the damage isn’t addressed, a purely cosmetic repair (filling, repainting) will not prevent the cracks from reappearing during the next drought episode. An independent counter-assessment can verify whether the proposed costing genuinely covers all necessary work, including any foundation reinforcement.
Were Fréjus and Saint-Raphaël covered by a drought natural disaster order in 2026?
Recognition of a state of natural disaster is assessed commune by commune and published in the Official Journal. For the relevant year and period, it is necessary to check whether an order was indeed published for Fréjus or Saint-Raphaël before filing a claim.
For any cracks that have appeared following a drought episode in Fréjus, Saint-Raphaël or the wider Estérel area, Cassini Expertise offers a free quote for an independent RGA assessment. Contact the firm on 04 22 46 06 04 or by email at [email protected].
Cassini Expertise
Expert du bâtiment indépendant — Antibes (06·83·13·40)
📅 Mis à jour le 25/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).