Major renovation and extension of the CASTOR building in a neighborhood whose architecture is marked by the 1970s.
The identity of the Beaugrenelle district in the 15th arrondissement of Paris is mainly due to the existence of twenty high-rise buildings connected by an artificial pedestrian floor located two levels above the natural ground : the slab. Fourteen towers are occupied by housing, two towers are dedicated to hotels and four high-rise buildings welcome commercial real estate. Some twenty low-rise buildings complete this tertiary sector park, which represents a total of some 130,000 sqm. of office space. HERTEL commissioned CALQ to reinvent the CASTOR building, one of the low-rise buildings on the Beaugrenelle slab.
Restructuring and densification
The CASTOR building will be occupied by a future business school of the INSEEC Group. It will be composed of an access hall, classrooms, activity rooms, rest and relaxation rooms, a cafeteria as well as support premises (teachers' room, offices for administration, meeting rooms, storage and archive rooms, sanitary facilities, technical rooms). The new project will result from the merger of two existing public establishments into a single public establishment to accommodate 1499 people.
Extension and work on the facades
CALQ wanted the building to regain coherence and legibility by rethinking the façades and working on the natural light contributions. The under slab facades of the ground floor and ground floor are advanced to regain a link with the public space. On the Quai de Grenelle, the facade is redesigned in asymmetrical folds to highlight the existing architectural elements, increase the views and light, offer intimacy to the classrooms vis-à-vis the public space, and energize and give rhythm to this very long facade (44 m) which is now smooth and monotonous.
The open spaces of the project (the roof terraces, the garden, the patio, the ground floor recess) will be vegetated. The project thus foresees an 88% increase in the vegetated surfaces.