29 May 2024


Preserving a historic monument: restoring stained glass windows at Le Mans Cathedral

The Cathédrale Saint-Julien du Mans is an emblematic religious edifice combining Romanesque and Gothic architectural styles, bearing witness to several centuries of history and transformations.

The cathedral’s foundations date back to the 4th or 5th century. It was levelled to build a new edifice in the mid-11th century. During this period, Romanesque elements, such as the nave, were built into the cathedral. In the 12th century, the Gothic section began to develop, with the choir and chevet completed in the 13th century. The chevet is particularly noteworthy for its inverted “Y” shaped buttresses, an innovation by architect Jean de Chelles, who was also involved in the construction of the Basilica of Saint-Denis and Notre-Dame de Paris.

One of the cathedral’s jewels is the fresco of the Angel Musicians, painted at the end of the 14th century on the vault of the Chapel of the Virgin. The fresco depicts 47 angels playing 24 different instruments, some of which have disappeared, such as the chessboard.

It has been listed as a historic monument since 1862.

Crézé’s mission: restoration and lining of protective glass and creation of new brass skylights

Under the aegis of the Architect, Mr Christophe Amiot, Head of Historic Monuments, the Crézé company took part in the restoration of the exterior of the Chapelle de la Vierge and its stained glass windows.

The restoration work carried out by our craftsmen involves restoring and lining the barlotières for the protective stained-glass windows. As a first step, we identified the location of the steel straps and steel strips on all the windows.

Crézé, Cathédrale Le Mans

In our workshops, we straightened all the straps and vergettes, and replaced any keys that were too damaged or missing. Strips, vergettes and keys were sandblasted and metallized. Barlotières could not be removed (fragile stone, barlotières sealed in lead), so restoration work was carried out on site. The original steel barlotières will also be fitted with white stained glass protective canopies.

Crézé, Cathédrale Le Mans

The creative work carried out by Crézé mainly concerns the creation of new brass barlotières. These barlotières will receive the old stained-glass windows restored by the four master glassworkers.

In our workshop, with the help of templates, we set to work making brass barlotières and straps.

Cathédrale Le Mans, Crézé

The finish is a brown patina. The frame and grille are dipped in a hematite bath. This is followed by a soak in an acid-neutralizing bath (water + sodium bicarbonate). The work is then blown-dried, and several coats of jade oil are applied to fix the patina.

Crézé, Cathédrale du Mans

The final stage in the creation of new brass bull bars is the installation of the perimeter frames and brass bull bars.

Crézé, Cathédrale Le Mans

Crézé is extremely proud and honored to contribute to the restoration of historic monuments in France. Drawing on our century-old know-how, we put our expertise and passion at the service of preserving architectural heritage. Each restoration project is a unique opportunity for us to perpetuate traditional techniques while integrating modern innovations, thus guaranteeing the durability and authenticity of the historic buildings we are fortunate enough to restore.