The new concrete roofs in major French churches after WW1 destruction, from patents to innovative practice

The pioneering experimentation around innovations and patents for reinforced concrete (RC) in early modern construction, as also their transition and application in large scale to mainstream technology, have been researched extensively. Less is known though on the role of patents and innovation in monumental reconstruction and their relationship with the practice and knowledge of traditional techniques, in contemporary preservation projects. Two French architects created very elaborate reconstructions of roof trusses for major churches in N. France heavily damaged during the First World War. They were both architectes-en-chef des monuments historiques (ACMH), but also affiliated with Anatole de Baudot, a pioneer of concrete architecture. Henri Deneux is well-known for his patented system of prefabricated light concrete bars in the reconstruction of the roof trusses in Reims Cathedral. His impressive designs are framed with two other churches in Reims (Saint-Jacques, before the cathedral and Saint-Remi afterwards) in a scheme called corset, where he gradually combined the truss with a concrete portal frame that braced the space above the stone vaults. A similar holistic engagement informed also same operations by Emile Brunet in the Basilica of Saint-Quentin, but with cast-in-situ frames. This paper explores whether this unified assembly was the outcome of a creative process initiated by the truss or a process freed from the original structural scheme of the destroyed vaulted space. The study examines also how far the designers believed the truss would firm up their control over the weak remains and the possibilities of a fertile debate among them.