The retail unit, located in Zurich’s high-end Bahnhofstrasse, is an important location for the Bucherer Group from Lucerne. As the world’s largest luxury watch and jewellery retailer with 36 sites in Europe and 32 stores in the US, the owner wanted the commercial building to stand out in a premium location following its renovation. 

The Zurich architecture firm Office Haratori and the architects at Office Winhov from Amsterdam were responsible for the design. The planners succeeded in reflecting the client’s industry in the building’s architecture. The renovation and the marble facade redesigned in 2017/2018 have now incorporated the commercial building into its surroundings. The renovated building simultaneously represents permanence, timelessness, innovation and perfection, the “core principles of Bucherer”, according to the architects. While the ground floor encapsulates bronze as a material, carefully arranged marble panels adorn the storeys above. The stone originates from Switzerland’s only marble quarry in the Canton of Ticino. “We precisely craft and redefine the marble from the Maggia Valley into jewellery-like elements”, the Office Haratori firm says about the design. “Like a sundial, the facade becomes an image of the daytime and of the seasons. The marble relief is sometimes flat and soft, then sharp and ordered depending on the movement of the shadows”.

The facade, which creates different atmospheres depending on the lighting, took a great deal of work for the civil engineers at blesshess AG from Lucerne. The building envelope also presented a challenge to those involved in the project’s planning and execution. Prof. Dr. Alfred Stein, the Ingenieurbüro für Befestigungstechnik IBT GmbH (Thür, Germany) and Medzech Ingenieure GmbH (Bad Homburg, Germany) were also heavily involved in planning and designing the facade. Meanwhile, Luchsinger & Partner GmbH (Quarten, Switzerland) and Natursteine Wüst AG (Wallisellen, Switzerland) planned and implemented the expert prefabrication and installation of the facade.

The facade consists of approximately 100 various steel tube grid constructions which are fitted with tapered pieces of marble of varying sizes and between 6 to 18 cm in thickness. These components were prefabricated by the manufacturer and were later hung from 6 to 8 studs on the construction site in a blind installation. The individual parts weighed up to 4.5 tonnes. Precisely placing heavy elements such as these without a central balance point while lining up with all the studs proved to be a tremendous challenge, particularly as the steel elements were deformed by up to 10 mm, which is unavoidable in steel construction. This hurdle was only overcome with a suspension device specially constructed for these elements. The fischer facade systems division of the fischer Group of Companies was responsible for fastening the marble panels to the steel construction using undercut technology. The undercut holes were drilled with a tolerance of less than 1 mm. This was a highly elaborate process, as Steven-Henrik Maier, Market Manager fischer facade systems reports. “There were challenges due to the heavy loads as a result of high dead load of the panels, which are up to 180 mm thick. Several pull-out tests were required to ensure correct and safe execution”. The tests were carried out with various panel thicknesses (30, 40, 60, 80 mm), including installation close to the edge and with larger panel sizes. A specialist anchor was ultimately designed featuring a higher anchoring depth to be able to carry the loads. 

The fischer solutions convinced the planners and architects in several aspects. From an aesthetic point of view, the option to conceal the panel fastenings was crucial. This was also the only option to feature the desired 2-mm joints in the element centre. Then there was the high load-bearing capacity, the technical support and the willingness to find and manufacture a custom solution tailored to the project. This solution consisted of the fischer Zykon panel anchors FZP II in the special 13 x 25.5 M8/18 Carbon variant, of which approximately 10,000 units were installed.  

The architects at Haratori found fitting words for the end result and described it, to quote Le Corbusier, as a “skilful, correct and magnificent play of surfaces assembled under the light”.