In full mutation, the Agroscope Center de Posieux, a reference institution of the Confederation for Agronomic Research, is the subject of a vast project aimed at bringing together its dispersed installations in a single campus, called to become its main seat.
In this context, a competition was launched in 2017 to replace existing reception infrastructure – a restaurant, a home and a conference room – which date from the start of 1970s. Having become obsolete, these spaces give way to a new project which marks the starting point for the transformation of the site.
The winning project, Papillondesigned by the Lausannois office Butikofer of Oliveira Architects1explore the potential of the pavilion: a light and open construction, an autonomous entity which arises in counterpoint with large agricultural infrastructure, while establishing a strong space dialogue with the entire site and the landscape.
A threshold between the near and distant landscapes
Below the main axis connecting posieux to Friborg, the agricultural plate on which the Agroscope extends offers a clear view of the Friborg Pre -Alps and dominates the left bank of the Sarine. This topographic configuration constitutes an asset for the establishment of the new building, discreet from the road thanks to the natural slope. Placed at the entrance to the site, it plays its role as an interface and a reception location, slightly overhanging existing laboratories and agricultural facilities.
Established in a close relationship with the site and the landscape, the project explores the tension between these scales, a form of complementarity which constitutes the starting point of architectural reflection: the pavilion must both welcome and radiate. It was essential for architects to design an object capable of detaching from the site to dialogue with the landscape, while registering in its immediate environment as a visual benchmark within the Agroscope.
Established exactly at the site of the old building, the new project adopts a clear and rational typology: the square plan develops in a horizontal, sober and unitary volume, covered with a large roof. The four fully glazed facades, extended by a peristyle, ensure continuity between interior spaces and the surrounding landscape.
Light as a material – a free space
Guided by a constructive wood-bouton logic offering great flexibility, this configuration is organized around a central space which articulates the entire program. Several architectural elements participate in the arrangement of spaces while part of an overall coherence.
In the center of the plan, a reinforced concrete belt ensures the loads of the roof floors up to the foundations, while allowing the opening of large breakthroughs. The structure responds to the architectural desire to set up four light wells, perceived as luminous opalin glass walls, the only function of which is to capture and diffuse natural light in all interior spaces. These walls do not establish hierarchies of use, but make it possible to articulate the different areas.
These walls diffuse a gentle and homogeneous light, without transparency or reflection, guaranteeing visual comfort and the quality of interior atmospheres. It is not only a relationship between emptiness and full, but an architectural choice, where the treatment of light becomes an essential component of the project. Here, we meet the idea of “light as material”-or even “light-radiant”, notions which refer to the categorization established by Henri Ciriani in his Clarity table2. This type of brightness arouses an emotion and transforms the perception of the place.
The kitchen – central element of the plane – is contained between these light walls. Around this nucleus, a continuous volume is deployed, structured symmetrically by the light from the large bay windows, in a constant relationship between the light walls and the landscape.
The structure, a spatial logic
Around the kitchen and the buffet are therefore deployed in a row the main functions of the building: restaurant, experimental restaurant3Aula, home and conference rooms. This provision promotes exchanges between users while ensuring a fluid transition between different spaces. Although designed according to a sequential logic, each space benefits from independent access from the outside, thus facilitating the reception of the public and the staff.
The main entrance, oriented towards the heart of the campus, is distinguished by a forecourt accessible via a staircase and a ramp leading to a large reception hall. This distributes a modular home-open to conference rooms via sliding walls-and the restaurant. A concrete staircase leads to a lower level partially open to the public, grouping sanitary, changing rooms, technical rooms, reserves and two large storage areas for neighboring laboratories. This basement efficiently brings together and compact the technical installations of the building as well as the campus data servers.
The entire project is based on coherence between structural logic and program organization. The basement and the ground floor, made of reinforced concrete, ensure both the foundation of the structure as well as a stable support for the wood structure. Peripheral openings in the slab, required for the installation of heating convectors, require underground buttresses to compensate for land thrust and guarantee the solidity of the whole. Extended to foundations, the service elevator cage also contributes to the resumption of seismic efforts.
Service access to the west allows direct deliveries to the basement. To the north, delivery access for the kitchen directly linked to the refrigeration area allows compliance with the cold chain. In continuity with the restaurant room, a terrace offers a large outdoor space.
Space modulation
With its apparent beam inside, the wooden structure contributes to the definition and identity of spaces. The vertical loads of the roof are taken up by mixed wood-button floors, divided into five solivages of different heights. This modulation makes it possible to adapt the heights under ceiling in a playful and technical way according to uses, with a continuous height for the restaurant, a more marked elevation for the conference rooms and a more intimate atmosphere in the hearth. These height variations make it possible to effectively integrate technical equipment – cameras, sound, lighting – directly in the ceilings, without harming the clarity of the spaces.
On the front, wooden cladding, adjusted to interior heights, make the organization of the building readable from outside. The subtle but essential qualities of his roof play an important structural role. Conceived as a “rigid diaphragm”, the latter transmits horizontal efforts to elements of bracing, contributing to the stability of the whole. It also makes it possible to integrate functional elements such as solar panels4.
Resting on an aligned colonnade with the interior wooden structure, each triangular facet of the roof is based on a pillar, with the exception of the four angles, left without support, creating the illusion of a slightly suspended volume. This detail gives the building a discreet dynamic-as if it turned on itself-a precision made possible by the structural logic of the project.
Notes
1. Oliveira Vernay Butikofer during the competition.
2. Henri Ciriani, “Table of clarities”, today’s architecture274, 1991, pp. 77-82
3. Experimental restaurants make it possible to study eating behaviors in real conditions, by collecting data on the choices, the quantities consumed and waste, in order to feed nutrition and durability research.
4. The project is part of a sustainability approach, meeting SNBS standards and the Minergie P-Eco label. The use of renewable energy sources, the installation of solar collectors and rainwater recovery systems bear witness to this environmental commitment.
Agroscope, posieux (FR) catering and conference building
Client: Federal Office of Constructions and Logistics (OFCL)
Architect Planning General and Works Department: Oliveira Boutikofer Architects Sàrl
Paysagiste: W+S Landschaftsarchitect AG
Civil engineer: Alberti Engineers SA
Uggin
Electrician engineer: BETELEC SA
Realization: 2022-2024
Surface: 2320 m2 (SUP 1113 m2)
