Building Endurance: Renovation and extension of the Zurich Kongresshaus and Tonhalle (2017–2021)

Abstract

The Zurich Convention Center (Kongresshaus Zürich, 1939) was designed by architects Haefeli Moser Steiger as a modern extension and further development of the late-nineteenth-century Zurich Tonhalle (1895). Starting as a centrepiece of the Swiss National Exhibition of 1939, the combined building complex has gradually become an important cultural institution and remains one of the most significant architectural works in Switzerland from the first half of the twentieth century. In the decades since its opening, the Kongresshaus and Tonhalle complex were further adapted in the 1950s and 70s, and controversially modified and renovated in the 1980s. This article aims to analyse key aspects of the renovation measures undertaken between 2017 and 2021 from a dual perspective—architectural and structural. In retrospect, it was the interdisciplinary collaboration that made it possible not only to preserve the integral spatial qualities of the building complex, but also to enhance them in a targeted manner. This process involved both the deconstruction of more recent structural additions and the necessary restoration and expansion of the historic load-bearing structures. Like Haefeli Moser Steiger’s original design, these recent interventions emphasize a distinct process known in German as weiterbauen, which stresses continuity and completeness in repair and renovation while respecting and enhancing the qualities of an existing work. While relatively little has been written or published on the recent renovation project, the proposed contribution brings to light a complex case study with important lessons for understanding an existing building and developing its overall and enduring qualities for a long-term future.