Centrale Lyon ENISE: To begin with, can you tell us where you are in your studies?
Valentin: I'm doing the double Architect/Engineer course between the Saint-Étienne School of Architecture (ENSASE) and Centrale Lyon ENISE. At the end of this year, I'll have two years of engineering left at Centrale Lyon ENISE. My brother, Anthony, is also in his 4th year of a double Architect/Engineer course, but between the École Nationale Supérieure d'Architecture de Lyon (ENSA) and the École Nationale des Travaux Publics de l'État (ENTPE).
Jean-Adrien: For my part, I completed my engineering degree at Centrale Lyon ENISE. I'm currently studying architecture at ENSASE.
Centrale Lyon ENISE : How did you meet and how did the Génies de la Construction project come about?
Valentin : We met about 4 years ago, during our studies. But we've had the opportunity to work together more recently in previous semesters.
Jean-Adrien: It was Valentin and Anthony who then came to me to talk about the Génies de la Construction competition, the bookshop project and their meeting with the owners. It was an opportunity to work together on a project that blends architecture and engineering, a discipline in which I have a little more experience.
Valentin: What we tried to defend through the project and the competition was precisely this dual architect/engineer training, which all three of us have. We share the same vision of the construction world. That of always having both an architectural and sensitive dimension, and a technical dimension, i.e. economic and technical feasibility.
Centrale Lyon ENISE: what's so special about the Génies de la Construction competition?
Jean-Adrien: The question of feasibility is an integral part of the competition des Génies de la Construction. In fact, that's what caught my attention. The feasibility is very interesting, as it blends engineering and architecture.
Valentin: With Anthony, we've already taken part in the Trophée Béton this year. This competition is more focused on architecture. "Les Génies de la Construction" is a benchmark competition in engineering schools that draws more on engineering. But it is tending more and more to emphasize cross-disciplinary knowledge. This can be seen in the profiles of the various teams who took part.
Centrale Lyon ENISE: What was the genesis of the project you presented?
Valentin: We worked on an emblematic bookshop in Bourg-en-Bresse, the Montbarbon bookshop. It has a beautiful history, spanning several generations. In October 2024, we met the owners. They told us they wanted to reinvest the 2nd floor of the building. It was a question of under-utilized space, loss of space, but also energy. In January 2025, the three of us made an initial site visit. Jean-Adrien was able to develop the specifications. After that, we worked on the project for 3 months before submitting it online on May 5.
Jean-Adrien: The essence of the project was to think about a vision of the bookshop over a 50-year horizon, with on the one hand the future of the bookshop from a programmatic point of view, i.e. what the owners want, and on the other hand the technical future in relation to global warming. We worked on the roof, which was not insulated. We came up with a solution that would withstand overheating in summer and let in enough light in winter. We also reworked the courtyard, which allows natural air recycling.
Centrale Lyon ENISE : What were the issues?
Jean-Adrien : The upstairs layout was the starting point. We thought about opening it up to the public, but that meant a lot of reorganization work: dimensioning the floors, taking down extra columns... So the idea was to move the offices up from the 1er floor to the 2ème to free up retail space. Our aim was therefore to refit the whole of the 2th floor to create a workspace for staff. On the first 1er floor, we reclaimed the office space by starting to make up for the floor level discrepancies.
Centrale Lyon ENISE : Were there any constraints regarding the building?
Jean-Adrien : The building dates from the 19th century. It has 60 cm-wide stone walls, a wooden structure on the upper floors, and a mixed roof: wooden Polonceau framework and glass roof with metal framework.
Valentin:The bookshop is a former coaching inn. So we worked on a building with a strong heritage value: façade, stone molders, Polonceau framework... This building is also located in a city center with adjoining buildings. So we also thought about our project on the scale of the block and the town center, to improve the whole for the inhabitants and users of the bookshop.
Centrale Lyon ENISE: Let's continue with the project itself...
Valentin: We tried to restructure the building around two voids: the atrium under the glass roof, which is the central axis of the programs (literary café, children's space...) and the outdoor courtyard. Our project is based on the spatial, thermal and programmatic interaction between these 2 voids.
Centrale Lyon ENISE: In your opinion, what made you stand out to the jury?
Jean-Adrien: I think it was the way we thought through the project and imagined a complete solution blending architecture, engineering and an understanding of the existing. Starting with a bookshop in the city center and an old building with technical qualities, we proposed light modifications that met the owners' needs and environmental issues. Our project presents low-tech solutions that integrate architectural and engineering qualities.
Valentin: Dealing with a building in the city center was an opportunity to tackle some very topical urban issues, first and foremost overheating and heat islands. Then there's density. Taking over the top floor is a way of expanding the bookshop vertically.
Centrale Lyon ENISE: How did the three of you work together?
Jean-Adrien: Anthony worked on a 3D BIM model. Valentin drew the plan and sections on the computer. This gave us a good understanding of the existing structure. Next, I developed a structural model to understand the building and integrate the new operating loads linked to the roof modifications. At the same time, I carried out a thermal study and a thermal model.
Valentin: We benefited from Jean-Adrien's knowledge, as he was ahead of us in the curriculum. For example, we were able to justify our architectural choices thanks to his engineering expertise.
Jean-Adrien: For my part, I really benefited from the graphic representations and their way of linking architecture and engineering.
Centrale Lyon ENISE: How would you sum up this experience?
Valentin: I think all three of us see our master's degree as an opportunity to open up, to get out of school projects and meet professionals. We wanted to seize this opportunity, test our skills and confront ourselves with the real world.
Jean-Adrien:For my part too, I enjoyed meeting professionals with very different backgrounds. We received different feedback from those we get at school. THE challenge was to get to grips with the professional world in which we'll be evolving in some time: deadlines, relationships with project owners... A successful challenge!"