Office Building Claridenstrasse 35

The new office building of the Balzan Foundation is located in central Zurich, close to Paradeplatz. Like the previous office building from the 1960s, it stands alone, but it is integrated into the existing perimeter block through its placement and size. The façade, articulated by horizontal elements of artificial stone and vertical metal profiles, echoes the inner load-bearing structure of concrete floor slabs and steel composite columns. The publicly accessible ground floor as well as the fourth and the top floor are accentuated by an expanded grid within the façade composition. Visitors are welcomed by a two-storey entrance hall facing the city. In memory of the institution’s founder, terrazzo flooring and sumptuous light fixtures lend the spacious entry Italian «grandezza».

The interior fit-out of the premises for the tenant, an audit and consulting firm, was conceived and created in tandem with the core and shell construction. The layout of the partitions, built-in furnishings and the custom-designed LED lighting are thus an integral part of the architecture.

The structural and energy concept of the building was optimized in order to add another storey within the specified building height, but without sacrificing room height. The loadbearing and bracing core, moderate spans and distances between columns ensure slender ceilings despite the strips of sound-absorbing elements and the pipes of the thermo active component system which are invisibly embedded in them. Ventilation with decentralised façade units and central extraction allows raised floors with minimal thickness. For heating and cooling, the compact building volume is connected to an anergy grid fed with lake water. A photovoltaic system is installed on the roof.

On the outside, the polished concrete of the prefabricated façade elements covering the edges of the floor slabs refers to the terrazzo surfaces of the interior, whereas the vertical profiles of anodized aluminium conceal both the loadbearing columns and the slender, individually operable ventilation flaps. The profiles are rectangular or round, closed or perforated, so that they can be read as both columns and «fresh air ducts».

A spacious forecourt along the street takes the place of the former parking lots. Broken stone slabs with greened gravel joints along with trees and shrubs recall the front yards once common in the erstwhile residential neighbourhood.

Location Zurich, Switzerland

Programme Office building, 7 floors above ground, 2 basement floors of the existing building, two-storey entrance hall, offices, meeting rooms, boardroom, 2 terraces, common room, underground parking with car lift

Competition 2015

Planning/Construction 2015–2018

Client Internationale Balzan Stiftung-Fonds

Gross Floor Area 4‘062 m2

Team G/G Stefan Thommen, Daniela Schadegg, Ivana Beljan

Construction Management Ghisleni Partner AG, Rapperswil/ Zurich

Landscape Architecture Schmid Landschaftsarchitekten GmbH, Zurich

Cost Planning/Scheduling Ghisleni Partner AG, Rapperswil/ Zurich

Structural Engineer Dr. Lüchinger + Meyer Bauingenieure AG, Zurich

Electrical Engineer Amstein+Walthert AG, Zurich

Building Physics Engineer BAKUS Bauphysik & Akustik GmbH, Zurich

MSR Amstein+Walthert AG, Zurich

Heating/Cooling Amstein+Walthert AG, Zurich

Ventilation Engineer Amstein+Walthert AG, Zurich

Acoustical Engineer BAKUS Bauphysik & Akustik GmbH, Zurich

Facade gkp fassadentechnik ag, Aadorf

Traffic Engineer Enz Partner GmbH, Zurich