This case study presents the renovation on an occupied site of the La Pléaide teaching high school in Pont-de-Chéruy (38), carried out in 2015 by the SPL OSER.

Renovation on an occupied site

The school provided lessons continuously throughout the work. Operations therefore had to adapt to this constraint. The choice was made to carry out most of the work during the school holidays. For work carried out during the course, such as insulation from the outside, days such as Saturday and Wednesday afternoon have been favored in order to avoid noise pollution. A great deal of consultation with users and planning was carried out to organize the site. Thanks to this, there was no need to relocate the classes during the work.

Do with the existing architecture

The project leaders have chosen to keep the atypical architecture of the school. Indeed, during its construction, the architects decided to create an establishment with a complex shape. The joinery in particular presented cases and shapes quite varied. There were also large windows and curved walls, which had to be accommodated in the renovation. The promoters of the renovation project also had to take into account the very location of the school in space, which is organized like a small village with a central alley open to the city. The former architects who worked on the construction of the school were consulted and gave their agreement on the renovation project.

A contract that includes energy performance guarantees

The renovation of the school is based on an Energy Performance Contract (CPE) signed for 10 years. Efficient heating systems have thus been installed by the consortium, in order to guarantee satisfactory results. The two existing boilers were replaced by two gas condensing boilers, supplemented by a gas heat pump. The DHW equipment was also replaced and hydroejectors installed.

A great deal of work has also been carried out on the envelope: reduction of the glazed surfaces, provision of inertia in the building by the external insulation ( 16 cm, R = 4.2m².K / W ), more efficient joinery, equipped windows sun screens, etc. Over the year 2018-2019, 38.1% of savings in primary energy were achieved for a contractual objective of 27%. The school also provides 16% of its energy consumption through a pre-existing photovoltaic installation, which is included in the CPE. Thanks to its elements, summer comfort is optimal in the establishment.

Sustainable development approach of the project owner

The primary objective of the project is fully in line with a sustainable development approach, since it involves improving the energy efficiency of the building, through extensive renovation work and the installation of efficient energy systems. The economic and social aspects are also present in the project: more than 50% of the services were provided by local VSEs and SMEs and the contract signed with the business group provided for 698 hours intended for people in professional integration. Finally, the project owner wanted to develop an educational component around the renovation: bridges were created between high school teaching, for STIDD classes for example, and the project.

Architectural description

The architect sought a "peaceful" architecture, which reconciles energy performance, summer comfort and simplification of solutions, while meeting the challenges of architectural legibility of the site. Indeed, the school was composed of complex shapes, in islands, without a common color code. The team therefore worked on the openings, colors and materials in order to have a more harmonious and uniform whole (off-white on the facades, anthracite on the joinery, etc.).