Plaster façades in Versailles: a period render still prescribed by the ABF

Antoine de Gironde

Oct 25

4 min read

Updated: 5 days ago

Restored plaster ornament on a façade, rue Mansart, Versailles

In Versailles, many façades in the historic centre are neither solid ashlar nor cement: they are rendered with exterior plaster. This is the material that the Architecte des Bâtiments de France (ABF) and the Plan de Sauvegarde et de Mise en Valeur (PSMV) most often ask to be reinstated during a façade renovation, depending on the building and its original condition.

Yet exterior plaster remains poorly understood: it is often thought to be an interior material, fragile in bad weather, or easily replaced by a contemporary render. Here is its history, how it is applied, and what such a project demands.

An urban history born under Louis XIV

In 1667, an ordinance of Louis XIV required Paris façades to cover their timber framing with plaster. Plaster then became a major material of urban façades across the Île-de-France.

Versailles, a new town built under Louis XIV, adopted the same construction logic. In the Notre-Dame and Saint-Louis districts, the façade rendered in coarse plaster became widespread over the 18th century, giving the townscape a clear, uniform order.

Plaster coloured through the mass

Traditional façade plaster is not covered with a film-forming paint. It is coloured through the mass at the mixing stage: its colour comes from the nature of the gypsum, the choice of sands and, where appropriate, mineral pigments dosed to approach the original historic shade.

This colour runs through the full thickness of the render. It gives the masonry a natural depth and avoids the premature ageing of modern paints, which eventually blister or flake.

Several traditional finishes

Exterior plaster allows different finishes depending on the architectural expression sought:

The cut or berthelé finish: the render is levelled then cut back with a berthelet (a toothed metal scraper), giving a regular, softened surface.

The thrown, washed or scraped finish: it reveals the grain of the sands to give the façade relief.

Imitation stone coursing: scored with a point into the fresh render, it imitates the bonding, joints and flat arches of an ashlar façade.

The eau-forte: a very diluted lime wash applied selectively as a last coat to patinate the whole, even out the tone and provide a protective skin without blocking the wall’s breathability.

Plaster and hydraulic binders: a risk of incompatibility

This is the fundamental technical rule: plaster must not be applied to a substrate containing cement or hydraulic lime, nor remain in prolonged contact with them. In the presence of moisture, the reaction between the components can form ettringite, an expansive mineral salt capable of bursting the render.

The most frequent mistake on old buildings is to apply a cement render to historic masonry. By blocking evaporation, it traps water, promotes the decay of the rubble stone and rules out a direct return to plaster without careful, complete hacking back to the original substrate.

Dealing with damp before rendering

In the Saint-Louis district, underground water flows and the nature of the soil favour rising damp at the foot of walls.

Rendering over damp masonry quickly ruins new work. Drying out the masonry, reviewing cellar ventilation and draining the base of the walls must all be settled before any re-rendering.

The role of the architect as project manager

On a plaster façade renovation, the architect secures every phase of the project:

The initial diagnosis: analysing the composition of the substrate, identifying damaged areas and checking for salts or residual moisture.

The specification (CCTP): defining the type of exterior plaster, ruling out incompatible mixes and including the repair of the protective elements at the top of the wall (zinc bands, cornices, overhangs) that guarantee the render’s longevity.

The administrative file: preparing the prior declaration of works needed to obtain the ABF’s approval.

Control on the scaffolding: having sample panels made directly on site to validate the dry shade, grain size and finish with the reviewing authorities before general application.

Work in progress: a building on boulevard du Roi in Versailles

On the ground floor of a classical building, the Atelier is leading the repair of an exterior plaster render imitating stone coursing. The layout of the flat arches and the radiating geometry of the voussoirs above the openings were set out directly on the scaffolding with the craftsmen, to restore the original design.

Another exterior plaster project in Versailles: the restoration of the façades of the Maison du Modèle, rue des Tournelles, in the Saint-Louis district.

Frequently asked questions

Does plaster withstand rain on a façade?

Yes, provided the top of the façade is effectively protected (cornices, watertight flashings, roof overhangs) and regularly maintained. Many Île-de-France façades more than two centuries old are proof of it.

Plaster or lime: which should you choose?

It depends on the nature of the building, its masonry substrate and what the planning department and the ABF recommend. In Versailles, plaster is often the historic reference material in the protected area, while lime is preferred on certain bases or specific masonry. A prior examination of the substrate settles the question.