Stone walls
& façades.

The old walls of Chautagne — village houses, farms, outbuildings — are thick, often built of stone with lime or earth mortar. They have no damp-proof course: ground moisture naturally rises into the masonry, then evaporates through the faces of the wall. It is a balance, not a defect.

The problem arises when this evaporation is blocked. A cement render, a film-forming paint or an impermeable insulation fitted on the inside trap water in the wall. It then rises higher, freezes in winter, makes the stones burst and the coatings come away. This is the most common scenario in failed renovations of older buildings.

Hence the vocabulary heard on every renovation forum: breathable walls, rising damp, “letting the wall breathe”, “cement is unsuitable for stone”. These are not fads: this is building physics, and it determines every technical choice on the project.

Beyond the technical side, there are the rules. The Chautagne PLUi regulations, approved on 21 June 2022 and common to all eight municipalities, explicitly protect roof and façade features: projecting or outlined surrounds and quoins, and génoises.

In practice, a façade renovation cannot bury these elements under a uniform render. Dressed-stone window and door surrounds, corner quoins and génoises — those cornices of stacked tiles at the top of the wall — are part of the identity of local buildings and must remain visible.

Some buildings are also protected under Article L151-19 of the French Planning Code. On these buildings, any work affecting the external appearance requires permission and a project designed accordingly. We check this point before costing a façade renovation.

This is the trickiest question with older buildings, and the one where bad advice costs the most. Insulating a stone wall from the inside with insulation and an impermeable vapour barrier often amounts to creating a condensation point within the thickness of the wall.

The approach to follow is different: favour capillary-active, breathable materials, deal with the causes of damp first (rainwater, perimeter drainage, ventilation) before insulating, and accept that a thick old wall already provides thermal inertia that regulatory thermal calculations undervalue.

Our in-house design office determines the strategy case by case: type of wall, exposure, presence of damp, use of the rooms. There is no single solution — and certainly no universal solution applicable to every house in Ruffieux or Chanaz.

Depending on the condition and type of wall, the work ranges from simple repointing — redoing the joints in lime while keeping the stone exposed — to a full lime render, including localised masonry repairs and the replacement of weathered stones.

Treating the surroundings matters as much as the wall itself: an overflowing gutter, ground that holds water against the façade or cement render at the foot of the wall will ruin the best façade renovation. We look at the whole picture, not just the surface to be repaired.

We work in all eight municipalities of Chautagne — Chindrieux, Serrières-en-Chautagne, Ruffieux, Chanaz, Motz, Saint-Pierre-de-Curtille, Vions and Conjux — as a separate work package or as part of a complete renovation, as project manager or general contractor.