Between now and September and for the first time since the beginning of the 20th century, visitors to the city of Carcassonne (Aude) will be able to tour its entire interior rampart. Since March 2022, the Center des monuments nationaux (CMN) has been working to restore the eastern front of the enclosure, i.e. 300 m of curtain walls, and nine towers between the Narbonnaise gate and the Prisons tower. “Walkers will discover in its entirety an extraordinary architecture and varied points of view towards the outside but also over the city and its count’s castle,” says Franck Doucet, administrator of the castle and the ramparts within the CMN. The restoration also gives a fresh look to a work that has seen the centuries go by. “The facings of the ramparts were not in good condition,” explains the project manager and chief architect of historic monuments Olivier Weets. The sandstone taken from the plateau at the time of their construction was of poor quality and was greatly degraded by wind and humidity. In addition, the work suffered from fractures between two towers and their curtain walls, and entire masses of masonry were no longer properly held. »
Brush cleaning. Once the scaffolding was in place, the Correa company cleaned the surface of the two facades of the rampart, the patrol path and the towers. This operation was done by hand, with a brush and water, so as not to damage the facings, the skin and the existing joints representing the know-how of an era. “The ramparts contain seventeen centuries of the city’s history, the challenge was to preserve this archaeological texture of the monument,” emphasizes Franck Doucet. In total, 18,000 m2 of stones were treated in this way. After a health inventory and a layout of the structure, the company then replaced the most damaged ones. “There are no more quarries in the region that would have provided us with local sandstone with similar characteristics. We therefore had to go and get it in Spanish Catalonia,” explains Olivier Weets. The stones are then hand-cut on site and their finish is adapted to their neighbours to blend in as much as possible. “We create harmonising patinas with pigments, water and sometimes a little lime to bring the stone closer to the appearance it will have in a few years,” explains Lionel Chabalier, site manager for Correa. This artificial colouring will gradually deteriorate in favour of the natural patina which will take its place.” A delicate operation repeated on the 250 m3 of stones replaced.
Two of the nine towers thus restored were also the subject of structural reinforcement. “Analyses during construction have made it possible to find less intrusive solutions than drilling and injections into the ground and inside the towers, which are complicated in particular for reasons of access,” indicates Lionel Chabalier. Instead, Correa carried out a remeshing by injecting a slurry of binder into the cracks of the masonry to recreate cohesion. Stainless steel tie rods, 28 for each tower, consolidate the structures and support wooden floors which act as a diaphragm by absorbing possible deformations. “We are both respectful of tradition and use a technique that is part of our times,” believes Christophe Robert, operations manager at the monument and collections conservation department at the CMN. The contemporary works – railings, emergency staircases – have been designed to fit seamlessly into the historic city.
Technical informations
Project management : Center for National Monuments.
Subject mastery : Olivier Weets, ACMH.
Works companies : Correa, subsidiary of Vinci Construction (masonry), Sud France (carpentry), Rodrigues Bizeul (roofing), Centre Sud Echafaudages.
Works duration : 31 months (March 2022-September 2024).
Cost : €5.6 million, including €4.5 million from the France Relance plan.
