# Facade Cracks and Rainwater Drainage Diagnosis – Cannes – Case Study

> Cracks on facades and inside, drainage review, markings for monitoring: a real crack survey in Cannes (06) with a 13-page report.

- URL : https://cassini-expertise.fr/en/facade-cracks-drainage-diagnosis-cannes/
- Langue : en-US
- Mis à jour : 2026-11-07
- Site : Cassini Expertise (https://cassini-expertise.fr/)

By Cassini Expertise – Independent building expert · Menton, Nice, Antibes, Cannes, Toulon · [+33 4 22 46 06 04](tel:+33422460604)

**In brief.** Single-storey detached house, Cannes area (06). External and internal cracks, several of them through-cracks, partly concentrated at the junction of two volumes. The survey was completed with a visual diagnosis of drainage and rainwater management. On-site visit of about 1 h 30, 13-page written report with a time-stamped photo log.

Key data

| Scope | Crack survey and visual diagnosis of drainage and rainwater management |
| --- | --- |
| Defects | 16 cracks catalogued and referenced for monitoring, several of them through-cracks |
| Points of attention | Junction of two volumes with no movement joint · poorly managed rainwater · mature vegetation close to the building · area exposed to clay shrink-swell (RGA) |
| Methods | Non-destructive visual examination · plumb check · moisture readings at the foot of the walls with a moisture meter |
| Visit and deliverable | About 1 h 30 on site · 13-page written report with a time-stamped photo log |

## Background

The property is a single-storey detached house of rendered masonry with Roman-tile roofing, made up of **two adjoining volumes with no visible movement joint** where they meet. The surroundings combine a paved terrace along part of the perimeter, a small yard at the foot of the facade, a narrow side passage and mature vegetation – including an old tree and tall conifer hedges – very close to the building.

## The question asked

The owner had noticed cracks on the facades, inside (walls, ceilings) and on the outdoor paving. Three practical questions: where do these cracks come from? Are they a sign of a structural problem? Does the rainwater drainage system play a part? The assignment covered the crack survey, a visual diagnosis of the drainage, and the marking of the cracks so that their evolution could be monitored over time.

## How the visit went

The survey, visual and non-destructive, followed a methodical order: a full tour of the outside (facades, downpipes, gullies, yard, vegetation in contact with the building), then a room-by-room inspection inside – bathroom, bedroom, hall at the junction of the two volumes, storeroom – and finally the roof. A **plumb check** was carried out at the junction of the two volumes, and moisture readings were taken at the foot of the walls with a moisture meter.

## Key observations

### Cracks concentrated at the junction of the two volumes

![Corner crack at the junction of two building volumes](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-fissure-jonction-f11-771x1024.jpg)

*The junction of the two volumes concentrates the damage: open corner cracks.*

In the hall, where the two adjoining volumes meet, the survey found open corner cracks and cracks along the door frames – the typical signature of **differential movement between two parts of a building**.

![Open crack along a door frame](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-fissure-chambranle-f12-771x1024.jpg)

*Along the frames, cracking follows the weak points of the masonry.*

### Through-cracks inside

![Crack running through the wall tiles of a bathroom](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-fissure-faience-f9-771x1024.jpg)

*The crack runs through the wall tiles: the substrate moved, not just the finish.*

In the bathroom, a crack **runs through the wall tiles** – the substrate has moved, not only the finish. In a bedroom, the ceiling shows stair-step cracking along the corners.

![Wall-to-ceiling cracks in a bedroom](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-fissure-plafond-f10.jpg)

*Wall-to-ceiling cracks and stair-step cracking in the ceiling: the indoor survey documents the damage.*

### Rainwater poorly managed at the foot of the building

![Clogged drainage gully in a small yard](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-avaloir-encombre-771x1024.jpg)

*A clogged gully lets water stand against the wall.*

Several findings point the same way: a clogged gully in the yard, a downpipe discharging at paving level, and render lifted by damp under the canopy. The moisture readings at the foot of the walls document the condition of the substrate.

![Moisture reading at the foot of a wall with a moisture meter](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-humidimetre-771x1024.jpg)

*Every suspect area is measured with the moisture meter.*

### A vegetation and geotechnical context not to be overlooked

![Old tree overhanging the gutter](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-olivier-gouttiere-771x1024.jpg)

*A mature tree right next to the building: a documented factor in the file.*

An old tree stands a few metres from the main crack, and conifer hedges run along the gable at very short distance. In an area where the municipality identifies zones exposed to **clay shrink-swell (RGA)**, this mature vegetation is a documented factor in the file.

## Analysis and deliverable

The 13-page report sets out the complete crack catalogue (each crack referenced and located so that it can be **monitored over time**), the drainage observations, the vegetation and geotechnical context, and ranks the probable causes. As the survey remained visual and non-destructive, the report states its limits and recommends the further investigations that would be useful.

![Plumb check at the junction of the two volumes](https://cassini-expertise.fr/wp-content/uploads/2026/10/ec1-controle-aplomb-771x1024.jpg)

*The plumb check puts a figure on the difference between volumes.*

## What this assignment shows

A crack cannot be judged by eye, in isolation: it is catalogued, measured, and set against the drainage, the vegetation and the local geotechnical context. It is this method – complete, documented, with a report that can be relied on in a dispute – that lets the owner decide with full knowledge. To go further: our [cracks and subsidence expertise on the French Riviera](https://cassini-expertise.fr/en-cracks-subsidence-expert-french-riviera/), or [our building expert service in the Alpes-Maritimes](https://cassini-expertise.fr/en-building-expert-alpes-maritimes-06/).

**See also:** [damp converted basement – Villeneuve-Loubet](https://cassini-expertise.fr/en/damp-converted-basement-villeneuve-loubet/) · [origin of damp at the base of a wall – Vence](https://cassini-expertise.fr/en/origin-of-damp-wall-base-vence/) · [all case studies](https://cassini-expertise.fr/etudes-de-cas/)

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Source : https://cassini-expertise.fr/en/facade-cracks-drainage-diagnosis-cannes/