Sanary-sur-Mer: Clay Soil, Subsidence and Cracks – Official Data

Damp in a wall can have four causes – rising damp, water ingress, condensation or a leak – and the treatments are completely different depending on the origin.

A reader in Sanary-sur-Mer writes to me, worried about dark marks at the foot of a wall. He has read online that resin injections are needed, or a mechanical ventilation system. My message: not so fast. Until the exact cause is identified, any treatment is a gamble – often costly, sometimes useless.

The 4 causes and how to recognise them

• Rising damp: a stain at the foot of the wall, climbing gradually, often accompanied by efflorescent salts and blistering render. Common in older buildings, on the ground floor, near the sea as in Sanary.
• Water ingress: a stain coming from above or from a specific point (crack, roof, joinery), often rain-related.
• Condensation: mist, mould in cold corners, poorly ventilated rooms (bathroom, kitchen), worse in winter.
• Leak: a localised stain near a pipe, an upstairs bathroom, that appears or worsens in bursts.

The trap of the diagnosis sold by the treatment contractor

Many companies focused on damp treatment offer a “free quote” – which almost always concludes rising damp, treated by injection. Commercial logic, but problematic: if the real cause is water ingress or condensation, the injection will solve nothing and the problem will return, after pointless spending.

Before any commitment, request an independent diagnosis in Sanary-sur-Mer, carried out by an expert with no commercial interest in selling the treatment: contact us here. To go further, also read the damp guide for 06, 83 and 13.

The geological and climatic context of Sanary-sur-Mer

Sanary-sur-Mer has a characteristic relief that explains the frequency of the losses we record on the ground: a town centre and a seafront built on relatively flat ground, framed by hills and small valleys where, since the 70s-80s, many estates of Provençal villas and more modern constructions have developed, often with a pool and a garden planted with pines and oaks. These hillside developments, common towards the Beaucours heights or in the direction of Six-Fours, very often rest on shallow foundations, designed at a time when the behaviour of the local clay soils was poorly understood. Yet the Var subsoil, rich in marly clays, shrinks sharply during summer drought before swelling again with the autumn rains, creating differential movement that weakens poorly anchored foundation footings. On villas of this generation we regularly observe façade cracks that follow the shrink-swell cycles, aggravated by the proximity of tall trees – pines in particular, whose roots pump moisture from the soil and intensify the differential settlement phenomenon near the foundations. The successive extensions and renovations of these houses, added without always upgrading the original foundations, also create points of differing stiffness that concentrate structural damage during these climatic episodes.

Sanary-sur-Mer: drought, clay and cracks – what the official data says

Can your cracked house in Sanary-sur-Mer be linked to drought? Yes, very probably: the GASPAR database records 5 drought prefectoral decrees (full list below) and 7 flood decrees, i.e. 12 natural disaster declarations (Cat Nat). Local rainfall confirms this diagnosis: three deficit years (2020, 2022, 2023), then a rebound to 827 mm in 2024 – it is this dry/wet cycle that cracks the foundations of Provence’s most photogenic port.

Cassini Expertise, an independent building expert, handles cracks and drought-related damage in Sanary-sur-Mer and throughout the Var. This page brings together the commune’s official data to help you work out whether your case is affected, with no commercial slant.

Natural disaster declarations (Cat Nat) in Sanary-sur-Mer: check whether your loss is covered

The GASPAR database (decrees published in the Journal officiel since 1982) records 12 natural disaster declarations (Cat Nat) for the commune:

• 5 drought prefectoral decrees (differential ground movement linked to clay shrink-swell (RGA))
  • event of 01/04/2017 (prefectoral decree of 18/09/2018)
  • event of 01/01/2018 (prefectoral decree of 16/07/2019)
  • event of 01/04/2019 (prefectoral decree of 07/07/2020)
  • event of 01/04/2020 (prefectoral decree of 27/07/2021)
  • event of 01/04/2022 (prefectoral decree of 03/04/2023)
• 7 flood prefectoral decrees and storm

First thing to do: place the appearance of your cracks in time. If it corresponds to one of the recognised periods above, natural disaster declaration (Cat Nat) compensation is possible – provided you declared the loss to your insurer within 30 days of the decree. If you missed that deadline, or the date matches no decree, the action against the seller for hidden defect (vice caché) or fraud (dol) remains (see below): there, a survey that precisely dates the damage becomes your best weapon.

The official clay classification (GéoRisques/BRGM): what to check before buying

The GéoRisques platform (BRGM) classifies Sanary-sur-Mer at high exposure to clay shrink-swell (RGA), with some sectors at medium exposure. This is the level your insurer and your notaire already look at to assess the risk on a given plot – you can consult it yourself on georisques.gouv.fr before signing. Another point to check on the same platform: the class 3 radon potential recorded in the commune (IRSN/GéoRisques data), a subject not to be neglected if you spend time in a basement or on the ground floor.

This classification completes the decree history above: the hazard rating says what can happen, the decrees say what has already happened. If your house is rated “high exposure” and has come through one or more of the last ten years’ dry summers, assume the risk of damage is real, not theoretical.

The complete chronology of the 12 natural disasters recognised in Sanary-sur-Mer

Each line = an event recognised by an interministerial decree published in the Journal officiel (GASPAR database):

• 🔵 09/1982 → 09/1982 – Floods (prefectoral decree of 24/12/1982)
• 🔵 08/1983 → 08/1983 – Floods (prefectoral decree of 15/11/1983)
• 🔵 09/1993 → 09/1993 – Floods (prefectoral decree of 08/03/1994)
• 🔵 01/1999 → 01/1999 – Floods (prefectoral decree of 23/02/1999)
• 🔵 09/2014 – Floods (prefectoral decree of 29/12/2014)
• 🔴 04/2017 → 12/2017 – Drought – clay shrink-swell (RGA) (prefectoral decree of 18/09/2018)
• 🔴 01/2018 → 03/2018 – Drought – clay shrink-swell (RGA) (prefectoral decree of 16/07/2019)
• 🔴 04/2019 → 09/2019 – Drought – clay shrink-swell (RGA) (prefectoral decree of 07/07/2020)
• 🔵 10/2019 → 10/2019 – Floods (prefectoral decree of 30/10/2019)
• 🔴 04/2020 → 06/2020 – Drought – clay shrink-swell (RGA) (prefectoral decree of 27/07/2021)
• 🔵 09/2020 – Floods (prefectoral decree of 10/02/2021)
• 🔴 04/2022 → 06/2022 – Drought – clay shrink-swell (RGA) (prefectoral decree of 03/04/2023)

Expert reading: 5 droughts and 7 floods. Clusters (several decrees close together) flag up crisis periods – the summer of 2022-2023 is the best recent example. An owner whose damage dates from a covered period has a solid Cat Nat file; outside a covered period, the way forward is an action against the seller.

The official clay classification (GéoRisques/BRGM)

The GéoRisques platform (BRGM) classifies Sanary-sur-Mer at high exposure to clay shrink-swell (RGA), with some sectors at medium exposure. This is the benchmark level used by insurers and notaires to assess the risk on a plot. Worth noting: radon potential class 3 across the commune (IRSN/GéoRisques data) – a health-and-building watch point in the affected zone.

This classification completes the decree history above: the hazard rating says what can happen, the decrees say what has already happened. A house rated “high exposure” that has come through one or more dry summers carries a risk of damage that is all the better documented.

What the official clay mapping says

The GéoRisques platform (BRGM) classifies Sanary-sur-Mer at high exposure to clay shrink-swell (RGA), with some sectors at medium exposure. This is the benchmark level used by insurers and notaires to assess the risk on a plot. Worth noting: radon potential class 3 across the commune (IRSN/GéoRisques data) – a health-and-building watch point in the affected zone.

This classification completes the decree history above: the hazard rating says what can happen, the decrees say what has already happened. A house rated “high exposure” that has come through one or more dry summers carries a risk of damage that is all the better documented.

The local weather data: why cracks appear with a delay

Annual rainfall recorded on the Sanary-sur-Mer weather grid (Open-Meteo data):

• 2019: 877 mm · 2020: 482 mm · 2021: 760 mm · 2022: 559 mm · 2023: 577 mm · 2024: 827 mm
• Average over the period: 680 mm/year, driest year: 2020 (482 mm)
• Three deficit years: 482 mm in 2020, 559 mm in 2022, 577 mm in 2023
• Then a rise to 827 mm in 2024 (+22%)

Remember this: shrink-swell plays out in two stages. First the drought dries out the clay at depth (shrinkage, onset of cracking), then the return of the rain rehydrates the ground at a stroke (swelling, differential movement). If you own a 1970-2000 villa on shallow foundations, do not be surprised to see cracks appear 12 to 24 months after a dry summer – that is the normal delay, not a sign that the problem is suddenly getting worse.

Cracks in Sanary-sur-Mer: the signs that should make you call an expert

• A stair-step crack, passing through the wall, open by more than 2 mm
• A crack that evolves: fit a tell-tale (a band of plaster or a marker-pen reference on either side) and compare after a few months
• Associated damage: doors and windows sticking, tiles splitting diagonally, render bulging
• A house on clay soil, a tree close by, drainage in poor condition

If you build up several of these signs, do not repair straight away: first have the damage recorded and dated by an expert. In a commune that already counts 5 drought prefectoral decrees, it is this record that will determine your compensation or your claim – and will avoid masking a problem that will return.

Buying or selling a cracked house in Sanary-sur-Mer: your recourse

Between the recent drought decrees and the volume of transactions, quite a few properties are changing hands with damage kept quiet. If you discover cracks after the purchase, you have two levers:

• Hidden defect (article 1641 of the Code civil): serious cracks, not detectable at the viewing, predating the sale → price reduction or cancellation, to be claimed within 2 years of discovery
• Fraud (dol) (article 1137): the seller knew and concealed the damage → cancellation and damages, within 5 years; the commune’s GASPAR decree then helps underpin the file

In both cases, keep every written trace (surveys, exchanges with the seller) and appoint a property-law solicitor (avocat) for the legal side.

How a drought/clay survey unfolds in Sanary-sur-Mer

• Technical visit: crack survey and classification, crack-width measurements, functional damage
• Context: clay zone, the commune’s natural disaster declaration (Cat Nat) history (5 drought decrees), local drought episodes
• Costing of works: underpinning, injections, drains – with several scenarios
• A written report usable by the insurer or the solicitor

Independent expert, with no ties to any building contractor. Request a visit in Sanary-sur-Mer – see also our complete RGA and Cat Nat guide for 06, 83 and 13.

Soil surveys on clay ground: what the regulations say

The requirement for a prior geotechnical survey has applied since 1 October 2020 (ELAN law, art. 68); the new exposure map of 1 July 2026 widens its scope. This obligation, stemming from ELAN law no. 2018-1021, article 68 (decree no. 2019-495 of 22 May 2019), applies particularly to Sanary-sur-Mer (high exposure in the BRGM classification).

• What it changes for building: the soil survey is no longer an option – the ELAN law makes it compulsory in an exposed zone for every sale of building land and every construction contract. Adapted foundations, ground treatment, drainage arrangements: the specifications flow directly from the survey.
• What it changes when buying a recent property: ask whether the survey was carried out and which specifications were applied. A house built without following the geotechnical recommendations on clay soil is a medium-term cracking risk.
• What it changes when selling: the absence of a survey on a property built before the obligation is not a defect in itself – but if damage appears, a seller who knew about it and concealed it exposes themselves to an action for fraud (dol).
• The link with the data above: Sanary-sur-Mer combines high exposure with a well-documented history of drought decrees. Building or buying here without checking the nature of the ground means building on a known and measured risk.

Cassini Expertise handles these files: compliance checks between geotechnical specifications and execution, damage surveys on clay ground, second-opinion expert assessments. Request a consultation.

Damp, water ingress and rising damp in Sanary-sur-Mer

Frequently asked questions

Is Sanary-sur-Mer in an at-risk clay zone?

Yes. The Var is widely exposed to the clay shrink-swell (RGA) hazard (BRGM mapping, viewable on georisques.gouv.fr). In Sanary-sur-Mer, the 5 drought decrees recognised by GASPAR confirm the risk is anything but theoretical: it has already materialised five times in six years.

Can a cracked house in Sanary-sur-Mer be compensated under the natural disaster scheme?

Only if your damage can be tied to a period covered by a decree (latest recognised periods: 2018, 2019, 2020, 2021, 2023) and if you declared the loss within 30 days. Failing that, the action against the seller remains – and there, precisely dating the damage through a survey becomes decisive for your file.

Can the figures quoted on this page be checked?

Yes, you can cross-check them yourself: the decrees come from the GASPAR database (Journal officiel, open data, 2025 update), the rainfall from Open-Meteo weather archives for the Sanary-sur-Mer grid. Cassini Expertise does not adjust these data.

Drought right now (as at 04/10/2026)

In the commune: recent rain (3 days ago). Rainfall over the last 30 days: 29 mm, against roughly 53 mm expected at this time of year – a 45% deficit.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

This week’s drought watch (as at 05/10/2026)

In the commune: recent rain (4 days ago). Rainfall over the last 30 days: 29 mm, against roughly 54 mm expected at this time of year – a 46% deficit.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

This week’s drought watch (as at 12/10/2026)

In the commune: recent rain (5 days ago). Rainfall over the last 30 days: 66 mm, against roughly 61 mm expected at this time of year – an 8% surplus.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

Drought right now (as at 19/10/2026)

In the commune: no significant rain for 12 days. Rainfall over the last 30 days: 67 mm, against roughly 67 mm expected at this time of year – a 0% surplus.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

The aquifer against its historic record: what do 30 years of measurements say?

The reference piezometric station for the area (002KZYQ) has been monitoring the aquifer since 1984 – 30 years of records. As at 01/10/2026, the average level over the last thirty days is 103.09 m NGF (French ordnance datum). Across the whole record, the aquifer has spent only 11.3% of its time below this level: a very low level, rarely reached in the station’s history.

• Last equivalent episode: 04/09/2024 – 2.1 years ago
• Frequency: 28 similar episodes recorded since 1984, i.e. an annual return on average – in hydrologists’ language, a rare event
• Historic minimum: 102.04 m NGF, reached on 30/10/2022

This long memory changes how the risk is read: a low level is not just a weather episode, it is an event whose frequency is known. For a house on clay, it is this frequency that tells you the probability of fresh settlement – and therefore how urgent the precautions are.

Find out more: Article 1641 of the Civil Code and the hidden defects warranty (garantie des vices cachés), explained.

Survey carried out by Frédéric Faucouneau, independent building expert – Antibes, Alpes-Maritimes (06), Var (83), Bouches-du-Rhône (13). Find out more

📅 Last updated 06/11/2026 - Cassini Expertise, independent building expert – departments 06, 83 and 13.