Notre-Dame de Paris will soon reveal a light that no one has seen for centuries

For many months, Notre-Dame de Paris had become a metal cathedral. With scaffolding covering the interior elevations and the intrados (interior side of a vault or arch) of the vaults, it is difficult to imagine that it could turn out to be so beautiful. After the closure of a first collapsed vault in the north transept, in November 2022, the Lefèvre company (Hauts-de-Seine) continued the consolidation of the vaults and the reconstruction of the significant breaches in the nave, caused by the fall of the arrow.

A final vault of the nave closed in April 2023

Kamal Hattabi, operations director at Lefèvre, specifies: “ We proceeded in the same way for all the vaults of the cathedral, namely: purging the masonry joints of the voussoirs (cut stone used for the construction of a vault or an arch, Editor’s note) and keys (block of stone cut into a bevel which constitutes the ribs of the vaults) from the intrados and extrados (outer face of a vault or arch), consolidation by injection of thixotropic lime micromortar grout to fill the voids and give a unitary character to the work, repointing via the upper surface then creation of a lime-based structural screed reinforced by fiberglass mesh. The repointing of the lower surfaces, still based on lime micromortars, is then carried out before applying a harmonization patina. On the collapsed areas, the arch supports, installed during the securing phase, initially served as essential supports for the installation of the stone arches up to the key, then allowed the fixing of hoops (assembly of wooden parts used to give the desired curvature to a vault under construction) mobile, moved as you move forward, for the installation of the voutains. »

The last vault of the nave was closed in April 2023. Once the vaults had been restored, the keys had to be repainted, one of which in the choir had previously been resculpted by Ateliers Bouvier (Gard). “ All were in a very dirty state and had gaps in paint and gilding. We consolidated them, we reattached the parts that were coming loose and carried out retouching, explains Charlotte Ferber, decoration painter at Arcoa (Hauts-de-Seine). Finally, in compliance with the design of Viollet-le-Duc, we marked the arches of the vaults with a discreet red ocher net which highlights the purity of the architecture. » « The end of the restoration of the intrados of the vaults conditioned the removal of the scaffoldingconfirms Sébastien Faure, director of operations of the public establishment. A total of 1,200 tonnes of metal spread across a large part of the cathedral must be taken down and evacuated. »

Cleaning that moves at high speed

And it’s not just metal. The wooden hangers, installed between March and August 2021 under the ribs of the vaults to support them, must also be removed: “ We removed the hangers as the vaults were closed, following the same protocol as for their assembly, but in reverse. For rapid evacuation, the hangers were placed whole on material containers (platform integrated into the scaffolding allowing the supply of equipment and materials to all levels of it) then evacuated, still whole, by the oculi (circular opening surrounded by stones made in a vault and which serves as a keystone), thanks to the crane », explains Damien Brisson, technical director at Le Bras Frères (Meurthe-et-Moselle).

The cleaning of the cathedral is progressing at high speed. All the facings have now been restored as well as the chapels, with the exception of those in the choir which should be completed in the first quarter of 2024 and which will be de-scaffolded immediately. The guardrails of the stands were the subject of special treatment: “ Designed by Viollet-le-Duc, they were, in the 20th century, deported to the rear because they no longer corresponded to current tastesconfides Jonathan Truillet, “science and heritage” deputy to the deputy general director of the public establishment. They still played their protective role but we saw them less. Like all furniture items, they have been removed and dusted, and will be repositioned in line with the columns, their original location. They fit particularly well into the interior decor, as Viollet-le-Duc wanted. »

Discoveries during the restoration of stained glass windows

As for the stained glass windows of the upper bays, and in particular those of the choir, they are gradually returning to their place after having been restored by the Baudoin workshops (Val-de-Marne), the Atelier Mur Anése group (Yvelines), agent, and Claire Babet Vitraux ( Eure-et-Loir), the Manufacture Vincent-Petit group (Aube), agent, and Arts et Forges (Aube) and, finally, Vitrail France (Sarthe). They bring a new chromatic harmony to the space. “ We made discoveries while restoring these stained glass windows, particularly concerning their borders which have a very goldsmithing aspect and which bring a kind of sparkle of which we were not aware before the restoration », complète Jonathan Truillet. « Once the entire cathedral has been cleared of this scaffolding, some finishing touches will remain, as Sébastien Faure indicates. We still have to complete the cleaning and restoration of the lower parts, such as the column bases for example, which were inaccessible until now, and we will be able to begin the restoration of the floors. »

Other elements have also been restored, notably the furniture elements of the choir – made up of the sculpted group of the Wish of Louis XIII and wooden stalls from the 18th century – and, of course, the transept crossing. “ The vault of the crossing was closed in spring 2024. This operation lasted two months. It is a very complex vault made up of 7000 to 8000 stone voussoirs and the installation schedule is quite dense. », Indicates Pascal Prunet, chief architect of historic monuments, more particularly responsible for monitoring the reconstruction of the vaults. Its reconstruction required both the descent of the scaffolding necessary for the reconstruction of the spire and the release of the floor of the crossing, where it is supported, for the creation of the liturgical platform.
The Notre-Dame construction site seen from the sky – October 2024