<Extension Kongresshaus Zurich Forum, Zurich, 2005


The site intended for the new congress center prominently inhabits a sensitive transitional zone between the countryside and the city. Immediately adjacent to Lake Zurich, the view from the site extends across the park-like quays to the lake and the Alps in the distance. Here too, the earlier congress center, which opened in 1939, symbiotically joins the legendary Tonhalle Zurich, itself built in 1895 and awaiting renovation. To the east, on the other side of the Claridenstrasse, the site borders on the grounds of the Villa Roseau. This villa, built in 1845, stands between the Tonhalle and the Hotel Baur au Lac. Currently, the villa serves all year as a guesthouse. With the construction of the General-Guisan-Quay, it lost its lake access.

Of the designs submitted for the competition, only Diener & Diener took into account the surrounding architectural monuments, the Kongresshaus, the Tonhalle, as well as the Villa Roseau. Moreover, its design avoided the need to tear down the villa or the Kongresshaus, itself a key work of Swiss Modernism designed by Haefeli Moser Steiger. Closely following the intricate wealth of detail and material displayed in the material of the former Kongresshaus, the new ensemble seeks to create a sequence of distinct spatial experiences. The expansion aims to integrate the rooms of the former Kongresshaus as a unified structure into the volume of the Tonhalle and shape it into an urban structure. The structural shell of the new congress hotel stands superimposed in front of both buildings, much like a stage tower, and overlooks the theater or opera as a tall building structure. With this, even the Tonhalle gains a more immediate relationship with the lake. The actual rooms of the Congress Center are contained in the cubic structure that occupies most of the space along the perimeter’s eastern edge. The landscape offsets the individualistic building along the Schanzengraben, with the countryside establishing the defining backdrop.

The semi-transparency of the corrugated glass façade, the landscaping, as well as the large openings together serve to underscore the building’s connection to the landscape. This has also had an influence on the shape of the pillars, the lighting structure, and the interior walls.

In 2008, the citizens of Zurich City voted against purchasing the Villa Rosau, a necessary element to construct the controversial new Congress Center in line with Raffael Moneo’s design.

in collaboration with Peter Suter
Competition: 2005
Date: 2005
Client: Zürich Forum
Location: General-Guisan Quai, Zurich, Switzerland
Gross Floor Area (GFA): 18.740 m² (convention centre), 4.300 m² (new tonhall), 11.580 m² (hotel), 4.000 m² (public space)
Use / Function: convention centre, Tonhalle Renovation, Hotel
Structural Engineer: Conzett, Bronzini, Gartmann
Mechanical Engineer: PGMM Schweiz
Landscape Architect: Vogt Landschaftsarchitekten

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