The project for an office buiding in Boulogne Billancourt, France consists of the renovation of building B’s existing 10,402m² surface area, the redesign of the facade taking into account the overall structure, the renovation of the technical premises, and the optimizing of office surface space. The competition winning design by Atelier Zündel Cristea is conceived with the logic of functional flexibility in which a central technical core frees the 8 floors, including the ground floor, from bearing concerns.
Built during the 1970’s, building B forms part of a larger whole located at 122, avenue du Général Leclerc, in the Silly-Gallieni neighborhood. The complex is made up of 11 buildings for housing, situated in the northern section of the site, along with the two office buildings, interconnected at ground floor level via a shared lobby with accompanying spaces for businesses to the south. More images and architects’ description after the break.
The office section, formed of buildings A and B, is surrounded on all its external sides by public roads, with Avenue du Général Leclerc to the south, rue de Sèvres to the west, and rue de Bellevue to the east. The ground floor’s particular volumetric configuration, which extends 28m on both sides of building B, poses a problem regarding fire regulation accessibility from its facades. The structure of the facade is composed in part by architectural concrete poles spaced 1.60m apart. The façade’s weight-bearing elements are placed at 8.00m intervals. The architecture is conceived with its capacity to evolve forefront in mind: through this logic, which addresses the issue of flexibility, it is modern and contemporary.
The building requires a new architectural point of departure; the new project is justified in light of the evolution of conditions of usage as well as regards energy standards. The idea of remaining adherent to an economy of means, present from the beginning of the project, will continue to be followed. The problem of energy will be approached subtly, with the aim of upgrading the efficiency of the facades and facilities “to measure”, rather that simply applying current regulations brutally. The building’s facades will be wiped entirely clean of all superfluous element. The surrounding structure will be consolidated with the aim of obtaining good stability and an excellent full/empty relation (between 50 and 65% in glass). The resulting extra surface area created by the shifting forward of the floors will be utilized in the creation of five plant-filled loggias at the southern structural wall.
The building’s new skin will be a double ventilated façade of slight thickness. A weatherproof first layer, patterned with a 5X1.35m by 1X1.25 grid every 8m, fastened to the concrete structure, effectively seals the building. This layer will be composed of insulated aluminum paneling for the section in which it covers the concrete, and of double glass paneling for its bay openings. The full height of the glass section will be able to be opened at every other panel so as to facilitate easy maintenance and cleaning from the interior.
A ventilated second layer will be placed at 0.20m from the first facade layer towards the exterior. This layer assumes a number of roles: it protects the adjustable horizontal laminated blinds to be situated on the first weatherproof layer’s exterior; it reinforces effective sound insulation of the premises with respect to the surrounding roadways; it helps limit heat loss during cold periods through the creation of a sheath of air which, in hot periods, will be effectively ventilated to prevent overheating. And finally, it presents us a building with a smoother, more contemporary image. The idea of total flexibility is pursued throughout: through the uniform grid patterning of the facade paneling into 1.35m modules corresponding to the 1.35m modules of the suspended ceilings, and through the electrical and technical “irrigation” of the offices by means of raised floors and suspended ceilings.
On each floor there will be plant-filled loggias acting as the veritable green lungs of the building. The building’s new image will form both out of restraint regarding the economy of means and the taking into account of the client’s expressed wishes and needs. Our proposition highlights generosity of space, light, comfort, and wellbeing. The loggia green spaces planned at the southern structural wall carry important, additional architectural value, without the loss of Useable Surface. They will function like small gardens, naturally ventilated, spaces in which the building’s users can pause, take a breath, take in the view. Today more than ever businesses are sensitive to the image their facades present to the world, as well as to the amount of comfort they can provide their employees.
Architects: Atelier Zündel Cristea
Location: Boulogne Billancourt, France
Cost: 12,25 M€ (before tax)
Surface: 10,544 m²
Mission: Research and Construction
Project: Office Building Renovation
Environmental Approach: High Quality Environmental Standards 2010/LEED Certification Core & Shell 2009