With the volAare buvette, a temporary meeting place has been created on Kreuzacker Square in Solothurn, Switzerland, revitalising the public realm while enhancing and revealing the site's existing urban qualities. To achieve this, ern+ heinzl Architekten developed a reversible structure that is resource-efficient and adaptable to a variety of uses. Situated adjacent to the River Aare and overlooking St. Ursen Cathedral, the intervention strengthens the spatial and social connections between key parts of the city by linking the railway station, the historic old town and the riverfront through an accessible public gathering place.

The project originated from two initiatives launched by the City of Solothurn at the end of 2024, aimed at upgrading previously underused urban spaces. Rather than functioning solely as a food and beverage venue, the concept developed by ern+ heinzl Architekten understands the buvette as an open piece of public infrastructure that accommodates diverse forms of appropriation and use. Alongside its gastronomic programme, existing amenities—including the public book exchange and the adjacent pétanque court—remain integral components of the site. The objective is to create a public space that encourages people to stay without making consumption a prerequisite for participation.

The architecture is based on a consistent low-tech approach. The structure consists of standard modular scaffolding components enclosed by a simple timber slatted skin. By relying on readily available industrial building elements, the design avoids bespoke structural solutions. Prefabrication enables rapid assembly, straightforward adaptation to changing requirements, and complete dismantling without leaving permanent traces on the site. The project therefore embodies the concept of temporary architecture in its true sense—not as a provisional structure, but as deliberately reversible architecture.

A defining architectural feature is the transformation between its closed and open states. Each morning, the large folding shutters along three façades are lifted, opening the buvette towards the square and the River Aare with an inviting gesture. This transformation creates fluid transitions between interior and exterior spaces while reinforcing the relationship with the surrounding urban environment. The architecture thus responds directly to patterns of use and daily operation, becoming an active component of public life.

The spatial programme comprises a compact hospitality core containing storage and service spaces beneath a generously cantilevered roof. The roof provides shelter from the weather and, through carefully integrated lighting, contributes to the atmospheric character of the square after dark. The design makes deliberate use of existing spatial resources: mature trees provide shade, the river embankment wall serves as informal seating, and neighbouring amenities such as the public book exchange and pétanque court are incorporated into the overall concept. Rather than introducing new infrastructure, the project activates existing urban assets and complements them with an accessible, low-threshold public offer. The spatial organisation accommodates different modes of use. A linear serving counter allows commuters to enjoy a quick coffee in the tradition of espresso al banco, while also supporting longer stays by the riverside.

Within the broader urban context, the buvette complements existing amenities and enhances their visibility. Together with the public book exchange and the regularly used pétanque court, it creates a diverse public environment that welcomes a wide range of user groups. As a temporary intervention, volAare contributes to the revitalisation of Kreuzacker Square, promotes social interaction and diversity, and strengthens the perceived sense of safety in the public realm. The project demonstrates how new public spaces can be created through simple, reversible and resourceconscious means. Rather than producing an architectural object, it establishes a framework for social interaction, appropriation and urban vitality.