At the end of 2016, the teams of Eiffage Construction Grands Projets began the heavy restructuring of this building from 1986.
This rehabilitation has enabled:
- 35% increase in the surface area by raising the building with the construction of 7 upper levels on the circular boulevard and 3 other sides of the courtyard, thus adding an additional 10,000 m² to the total floor area;
- the separation of two adjoining volumes, highlighting its square shape;
- the renovation of the 7 existing floors;
- the expansion of work spaces with 2,700 m² trays.
The architecture of the building has been completely redesigned by the agency Crochon Brullmann & Associés, associated with the agency Architecture et Environnement. A 2,300 m² glass facade, signed by Goyer, a subsidiary of Eiffage specializing in the design and implementation of aluminum and glass facades, replaced the original sloping glass to homogenize the silhouette of the building.
The teams of Eiffage Construction had to face several technical challenges during this construction site forced:
- the establishment of a perfect synchronization between demolitions and constructions to ensure the maintenance of the bracing of the building;
- the installation of a pumping system from the beginning of the realization of the peripheral sails of basement due to the presence of a water table under the building;
- removal of 12,000 m3 due to the presence of a former station in the basement.
The renovated building shows a considerable reduction in energy expenditure, as well as in its water and heat consumption, both in terms of the organisation of the construction (recycling of waste, constructive methods, management of nuisances, etc.) and building design (choice of materials, organization of space, orientation of facades, management of HVAC).
The operation aims at the certifications HQE Renovation tertiary buildings level Exceptional and Breeam level Excellent, thus contributing to the upscale of the office park of La Défense.