Low consumption building (Effinergie)
“Office buildings and HQE Passport: Excellent” Certification
Winner of the 2016 SIMI Grand Prize, category “New office building + 5 000 m²” and winner of the 2017 ArchiDesignClubAwards, category “Office building”
A stone’s throw away from the station and facing the Cité des Congrès, the site is strategically located at the southern entrance to Nantes, in the ever changing district of the commercial area Madeleine – Champs de Mars. Adjacent to the headquarters of CIC Ouest, which is undergoing a restructuring with which the project must deal, the land is free of any construction and has a surface area of 4,300 m².
How can one organise the building in order to offer the most efficient and qualitative work ergonomics available? This question is the underlying principle of the project and will help resolve the issues arising from this operation: urban integration, environmental quality and construction of a bank headquarters in a context of financial crisis. The project is akin to an opalescent glass building offering transparent public spaces and translucent private spaces. It consists of two bodies of buildings: one, vertical, is anchored in the territory, in continuity with the existing CIC plots, like a watchman at the entrance of Nantes; the other, horizontal, seems to be levitating above the public space. In between, a “piazza” provides an urban bridge and enhances the public space. The whole project is articulated around this square, which extends towards the inside of the building, playing with transparencies and openings. A dialogue takes place between the geometries of the two buildings, where the slightly broken vertical and horizontal lines of the façades meet. The standard workspaces are divided into three thick levels (R+3, R+4 and R+5), with two patios. The ground floor, 1st and 2nd floors house public or collective functions (exhibition and reception rooms, cafeteria and restaurant) around a large reception hall, bathed in light and crossed by a suspended staircase. This configuration allows all offices to benefit from sufficient space and equal lighting. In addition, it promotes optimal communication and comfort of use thanks to the looped traffic. All these spaces are reconfigurable both spatially and thermally. Reducing heat resulting from radiation and sun rays on the façades was a guideline for the architectural design of the project. The building, supported by a metal structure, is completely covered with a double layer of silkscreened glass, laid down a metre from the first curtain wall. This second façade is an innovative heliotrope membrane that optimizes solar gains through motorised mobile glass panels connected to sensors, which automatically rotate to follow the sun’s path. During winter, the closed double skin creates a thermal buffer, while when opened in summer, it is a ventilated solar shading device. This façade design also provides an image of structure: a picture of a changing district, but also a perception of openness. The bank headquarters open onto the city from the inside and the activities being carried out within are also visible from the street. It is undoubtedly this combination of technical and architectural solutions that showcase the bond and approach shared by architects and engineers that provide their array of diverse skills to AIA Life Designers.
ClientCrédit Mutuel, CIC, Nantes
Main ContractorsArchitect: AIA Architectes
Interior architect: AIA Architectes and Mouvement carré (Stéphane Renaud)
Engineering + economy: AIA Ingénierie
Consulting firm façades: Arcora
Consulting firm environment: AIA Environnement
Scheduling, Overseeing, Coordination: AIA Management
ProgrammeConstruction of the Crédit Mutuel headquarters in the Loire-Atlantique department; restructuration of CIC (adjacent island composed of 9 plots and one block); reconfiguration of public spaces.
Surface(s)New headquarters of the Crédit Mutuel Loire-Atlantique: 14,000 m² / Restructuration of CIC: 16,300 m²
Cost€50M Tax-Free for the Crédit Mutuel HQ (value April 2013) / €27M Tax-Free for the CIC