Like a magician’s handkerchief, a folded sheet of untreated aluminium is placed over a C-shaped group of 19th century buildings. A found object, a New York-style staircase overlooking the train lines of Cornavin station with the Alps in the background.
A material, a treatment and a sober, fluid structure reveal the architectural qualities of the existing renovated facades, protected by the Commission for Monuments, Nature and Sites (CMNS). A clear contrast between the 19th century part and the contemporary vertical expansion, overlooking the station platforms.
The aluminium sheet is selected for its lightness (contributing to structural savings), the light it diffuses into the courtyard, its matt white patina preventing any mirror effect, its low radiation (compared to other metals, see energy concept) and its abstraction. A structure riveted to the metal substructure, avoiding any need for joints and evoking the construction of train carriages and the world of railway stations, as well as the caravans and other housing experiments by Buckminster Fuller, or even the sphere of aviation. These mobile architectures, like this vertical expansion project, must offer shelter and protection while remaining very light and fluid. The continuity of the courtyard cladding, roofs, sections of the facades and the wide, corniced window openings is achieved by a unique skin, with no difference as to the material or architectural treatment. It unites all of these traditionally distinct parts, neutralizing them in a strong, identifiable form.
The need to exploit this 19th century ensemble, whose qualities have been lost over its past 50 years of neglect, is evident, especially given its absolutely exceptional situation facing the station platforms. The reduction in height compared to the Rue des Grottes, the state of the roofs, and the relevance of social housing in the city centre (especially in the Grottes district) has inspired this vertical expansion. It unites the varied heights of the ensemble and adds some 740 m2 of gross residential floor area, while renovating around 1500 m2 on the existing floors.
