Respecting the recommendations made by Jean-Claude Marsan (member of the Historic Sites and Monuments Board of Canada and director of the conservation of the built environment program at the School of Architecture of the Université de Montréal), the architects of Provencher Roy + Associés Architectes meticulously restored the church’s envelope. Some parts that were too badly damaged were completely resculpted. The 146 stained-glass windows (including the 20 Tiffany windows) were removed, restored, and reinstalled behind glass panels that make the building watertight. Inside, the plaster ceiling and the mouldings were completely restored, as were the woodwork pieces adorning the nave.