Beausoleil: Clay Soil, Subsidence and Cracks – Official Data

Beausoleil facing drought and clay: what the figures tell

Your house is cracked in Beausoleil: is it the drought? The ground is indeed clayey, but the GASPAR database records no drought decree for the commune – here, the official record leans towards flooding (4 flood decrees since 1982, 4 decrees in total including storm), the commune overlooking Monaco on a relief exposed to runoff. On the weather side, the classic scenario is there: three dry years in a row (2021, 2022, 2023), then an abrupt rebound in 2024 to 1,221 mm (+60%) – precisely the alternation that cracks foundations in this belvedere of a commune.

Cassini Expertise, an independent practice, diagnoses cracks and drought-related damage in Beausoleil and throughout the department. This page brings together the official data specific to the commune, to help you determine whether your cracks fit this pattern and what to do next.

Can my house in Beausoleil be compensated under natural disaster provisions?

The GASPAR database (decrees published in the Official Gazette since 1982) counts 4 natural disaster decrees for the commune:

• 0 drought decrees (differential ground movement linked to clay shrink-swell)
• 4 flood and storm decrees

What you must check: each drought decree corresponds to a specific period. If your damage dates from a period recognised elsewhere in the 06, a Cat Nat declaration is possible (30-day deadline to observe). In Beausoleil, for want of a drought decree, that route is closed – what remains is the recourse against the seller, for latent defect or fraudulent misrepresentation, detailed below.

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

The GéoRisques platform (BRGM) classifies Beausoleil at high exposure to clay shrink-swell (RGA), with some sectors at medium exposure. This is the level insurers and notaires check before ruling on a plot – you can make the same check by entering the address on georisques.gouv.fr.

This ranking and the decree history are read together: the hazard tells you what can happen, the decrees tell you what has already happened. A house in a “high exposure” area that has come through one or more dry summers deserves a visual check even without any visible crack.

Forty years of decrees: the complete chronology of Beausoleil

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

• 🔵 11/1982 → 11/1982 – Floods (decree of 04/02/1983)
• 🔵 11/1982 → 11/1982 – Cyclones / Storms (decree of 15/12/1982)
• 🔵 10/1999 → 10/1999 – Floods (decree of 03/03/2000)
• 🔵 11/2000 → 11/2000 – Floods (decree of 19/12/2000)

Expert’s reading: 0 droughts and 4 floods. Clusters (several decrees close together) mark the 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 route is the action against the seller.

What the official clay mapping says

The GéoRisques platform (BRGM) classifies Beausoleil 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.

This ranking complements the decree history above: the hazard tells you what can happen, the decrees tell you what has already happened. A house in a “high exposure” area that has been through one or more dry summers carries a risk of damage that is all the better documented.

The official clay ranking (GéoRisques/BRGM)

The GéoRisques platform (BRGM) classifies Beausoleil 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.

This ranking complements the decree history above: the hazard tells you what can happen, the decrees tell you what has already happened. A house in a “high exposure” area that has been through one or more dry summers carries a risk of damage that is all the better documented.

Rainfall in Beausoleil: at what point should you worry?

Annual records on the Beausoleil weather grid (source Open-Meteo):

• 2019: 1,029 mm · 2020: 711 mm · 2021: 573 mm · 2022: 450 mm · 2023: 604 mm · 2024: 1,221 mm
• Average over the period: 764 mm/year, driest year: 2022 (450 mm)
• Three consecutive water-deficit years: 573 mm in 2021, 450 mm in 2022, 604 mm in 2023
• Then a rebound to 1,221 mm in 2024, i.e. +60%

Remember this two-stage mechanism: the drought dries the clay at depth (the ground shrinks, the first cracks appear), then the rain returns and rehydrates the ground in one go – swelling, differential movements. If you live in a 1970-2000 villa on shallow foundations, watch your walls 12 to 24 months after a marked dry or wet episode: that is the usual delay before damage appears.

The drought right now (as at 04/10/2026)

In the commune: recent rain (3 days ago). Rainfall over the last 30 days: 5 mm, against roughly 53 mm expected at this time of year – a 91% deficit.

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

The drought right now (as at 05/10/2026)

In the commune: recent rain (4 days ago). Rainfall over the last 30 days: 5 mm, against roughly 55 mm expected at this time of year – a 91% deficit.

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

What is the rainfall situation today? (as at 12/10/2026)

In the commune: recent rain (5 days ago). Rainfall over the last 30 days: 90 mm, against roughly 64 mm expected at this time of year – a 41% surplus.

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

What is the rainfall situation today? (as at 19/10/2026)

In the commune: no notable rain for 12 days. Rainfall over the last 30 days: 90 mm, against roughly 73 mm expected at this time of year – a 23% surplus.

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

Water table memory: 30 years of measurements, a well-documented context

The reference piezometric station for the sector (002FFSZ) has been monitoring the water table since 1997 – 30 years of records. As at 26/09/2026, the mean level over the last thirty days is 70.81 m NGF. Across the whole record, the water table has spent only 24.0% of its time below this level: a low level, in the lower quartile of known values.

• Last comparable episode: 30/10/2023 – 2.9 years ago
• Frequency: 19 similar episodes recorded since 1997, i.e. a return every 2 years on average – in hydrologists’ language, an intermediate episode
• Historical minimum: 65.58 m NGF, reached on 24/10/2022

This long memory changes how the risk is read: a low level is not merely a weather episode, it is an event whose frequency is known. For a house on clay, it is that frequency that informs the probability of further settlement – and hence the urgency of precautions.

Beausoleil: ground that calls for a local reading

Beausoleil is a special case in the department: the commune literally clings to the slopes of the Mont des Mules and the Moyenne Corniche, in direct continuity with Monaco, with housing stepping up in successive terraces on very pronounced relief. You find a fairly unique mix of early 20th-century stone buildings, packed into the historic urban fabric, and more recent 1970s-90s residences built into the hillside to take advantage of the view over the Principality, often with foundations that were not always designed for this type of steeply sloping ground. The clay soil, mixed with the marls typical of the massif, reacts strongly to variations in moisture: in periods of drought, the shrinkage of the clay beneath the shallow foundations causes differential settlement that translates into façade cracks, often diagonal near corners or above openings. The terraced layout compounds the phenomenon, as each building level experiences different stresses depending on its aspect and its anchorage in the slope. The Mediterranean vegetation – pines and olive trees in particular – whose roots pump the residual moisture from the soil beside the homes, further aggravates the local drying of the clay. It is an area where we are regularly called out for crack diagnoses, precisely because of this combination of pronounced relief, unstable clay soil and sometimes ageing constructions poorly adapted to these geotechnical constraints.

Rainfall: the commune’s long memory

The weather archives for the area cover 35 complete years (1991-2025). The driest ever recorded: 2007, with 451 mm over the year, against a local average of 820 mm. 2022 ranks as the 2nd driest year out of 35 (451 mm against an average of 820 mm); 2023 follows in 7th place (604 mm).

This ranking gives the true measure of the recent sequence: when the years 2020-2023 crowd into the top of the drought table, the clay has not had time to rehydrate between episodes – the classic scenario for delayed cracks. The reverse is just as instructive: a very wet year following an exceptional drought causes abrupt swelling of the ground.

Damp, water ingress and rising damp in Beausoleil

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.

You have noticed damp marks in Beausoleil and you may already have read that resin injections or a ventilation system are needed. My message: not so fast. Without a precise diagnosis of the origin of the problem, these works can be costly and totally ineffective.

The four causes and how to recognise them

• Rising damp: tide marks at the foot of walls, efflorescent salts, blistering render, only on the ground floor or in the basement.
• Water ingress: stains that follow the rainfall, often in the upper part, near a roof, a terrace or a crack in the façade.
• Condensation: misting on cold surfaces, mould in wall corners or behind furniture, worsened by lack of ventilation.
• Leak: localised stain near a pipe run, a bathroom or a kitchen, sometimes unconnected to the weather.

The trap of the diagnosis sold by the treatment contractor

In Beausoleil, the relief and the proximity of the sea multiply the configurations: semi-buried houses on the hillside, façades exposed to sea spray, old co-ownership buildings with damp basements. Many damp-treatment companies offer a “free quotation” before selling their own injection works. The problem: that diagnosis is never independent, since the company carrying it out has an interest in selling a treatment, whatever the real cause. Frequent outcome: injections billed at several thousand euros to treat rising damp… when the problem actually came from water ingress or a ventilation defect.

Before committing to works, have an independent diagnosis carried out in Beausoleil by an expert with nothing to sell but their analysis. You can also consult our damp guide for the 06, 83 and 13 to understand the treatments suited to each cause.

Which signs on my house should alert me in Beausoleil?

• Stair-step crack, through-wall, opening wider than 2 mm: measure it with a ruler or a crack gauge
• A crack that is evolving over time: fit a tell-tale (plaster or gauge) and check it every month for 3 to 6 months
• Associated signs to monitor in parallel: doors and windows sticking, floor tiles splitting diagonally, render swelling
• Aggravating factors on your plot: house built on clay, trees close by, drain in poor condition

With 0 drought decrees recognised in Beausoleil, a combination of several of these signals should prompt you to commission a survey before any repair – and before any commitment to buy or sell. Keep dated photos and the readings from your tell-tale: they are the pieces that will make the difference with an insurer or a lawyer.

I am buying or selling in Beausoleil: the house has cracks, what are my rights?

Between the recent drought episodes and the pace of transactions, properties regularly change hands with damage passed over in silence. If you are the buyer and discover cracks after the sale, two remedies exist:

• Latent defect (Article 1641 of the Civil Code): serious cracks, not detectable at the viewing, having appeared before the sale → price reduction or cancellation, to be asserted within 2 years of discovery
• Fraudulent misrepresentation (dol) (Article 1137): the seller knew and concealed the claim → cancellation of the sale and damages, within 5 years; the commune’s GASPAR history then strengthens the file

To engage this procedure, have a property lawyer at your side – the technical survey supports the legal file, it does not replace it.

How does a drought/clay survey run in Beausoleil?

• On-site visit: crack mapping and classification, opening measurements, functional damage
• Context: clay nature of the soil, the commune’s Cat Nat history (0 drought decrees), local drought episodes
• Repair cost estimates: underpinning, injections, drainage – several possible scenarios depending on severity
• Written report, directly usable by your insurer or your lawyer

For an on-site visit: building expert in Beausoleil.

Independent practice, with no ties to any works company. Request a visit in Beausoleil – also worth reading, our complete RGA and Cat Nat guide for the 06, 83 and 13.

Soil surveys on clay ground: what the regulations say

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

• What it changes for building: the soil survey is no longer an option – the ELAN Act mandates it in exposed zones for any sale of building land and any 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 heeding the geotechnical recommendations on clay ground 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 fraudulent misrepresentation.
• The link with the data above: Beausoleil combines high exposure with a documented flood record, although no drought decree has been issued. 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, surveys of damage on clay ground, second-opinion expert assessments. Request a consultation.

Frequently asked questions

Is Beausoleil among the clay risk zones?

Yes. The Alpes-Maritimes is very largely affected by the clay shrink-swell hazard (BRGM mapping, visible on georisques.gouv.fr). In Beausoleil, the absence of a drought decree in GASPAR does not mean the risk is absent – it simply confirms that the recognised historical risk here is flooding and slope movement, not drought.

Is my cracked house in Beausoleil eligible for natural disaster compensation?

Only if your damage can be linked to a period covered by a drought decree (check the recognised periods on GASPAR) and if you declared the claim within 30 days. If no decree covers your case – in Beausoleil as elsewhere if the property was sold in the meantime – turn to an action against the seller – and have the damage precisely dated by a survey, it is the central issue of the file.

Can I check the figures on this page myself?

Yes: the decrees come from the GASPAR database (Official Gazette, open data, 2025 update), the rainfall from Open-Meteo weather archives for the Beausoleil grid. Cassini Expertise reproduces this raw data, without adjusting it.

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

📅 Last updated 24/10/2026 - Cassini Expertise, independent building expert – departments 06, 83 and 13.