Text description provided by the architects. This rehabilitation is a clear opportunity for a new deal and provides the chance to offer all users a new working and living environment. The architectural challenge is to create a core, re-orient the polarities of the school, harmonise a high school made of heterogeneous buildings. The entire restructuring of the teaching building (externat) and the addition of a school library on the restaurant's terraced roof therefore allow students to find a coherence in its use. The coherence of the architectural design results from the use of white Trespa panels. The white facing of the teaching building becomes the scenic background for the white-striated homogenous block of pure volumes which hosts the school library and the restaurant on the schoolyard level.
The school library (Centre de Documentation et d’Information) reigns on a pedestal in the middle of the schoolyard. Built on the model of a peristyle room, it hosts the reading room in its centre. This superimposition, built from dry construction materials with a structure in galvanized steel, unifies the school library and the restaurant and gives to the whole the look of a white-striated homogenous block of pure volumes. The roofing rests upon a peripheral line of very thin galvanized steel posts, which encloses the central volume.
Finally, the floor has undergone a complete restructuring, through the creation of a concrete base and the integration of both stairs and access ramps; it sets the whole composition, prioritizes circulation, and leads naturally to the doors of the various buildings. To protect from the sunshine, the South-facing roof becomes gradually slimmer and ends up in a sizeable brim-like cantilever.
The Eastern and Western façades are protected from low-angled sun rays by perforated white vertical Trespa panels, running at right angles from the glass surface, mounted on pivots and linked together to an automated system. This system allows to control the building's permeability to the sun's rays for each façade, all the way to complete closure. In this ultimate position, the panels form a second skin 60cm from the façade. These vertical panels are also found at the lower level on the school restaurant's façades.
The teaching building went through a rehabilitation process. A covering of white Trespa panels on the façade, which had been isolated beforehand, as well as a double cap of perforated white Trespa panels (Trespa panels that match the coverings and the sun protections of the library) were put in place in addition to the new layout of the inside volumes.
Efficiency requirements in terms of materials and construction standards, energy management, isolation, summer thermal comfort, low pollutant-emission and building site management have been reached.
Heating consumption is 45.8 kWh/m²/year (average for the buildings). Before the rehabilitation, this consumption was 96.8 kWh/m²/year. This new consumption level is the combined result of the isolation efficiency of the outer layer, and of the energy-saving system. The energy-saving system includes the existing gas-powered boiler room, low-temperature heaters, double-flow ventilation for the library, and highly energy-efficient lamps.
The strong thermal inertia combined with suitable solar protection (overhanging roof and sun screens) and a nightly over-ventilation (doubled the normal ventilation flow) ensure an optimal thermal comfort during the summer.
The building site also followed the recommendations of the « low-pollution building site » charter.