In the course of the redevelopment of northern Zurich, the Technische Berufsschule Zürich (TBZ) was forced to give up its building on Affolternstrasse in Zurich-Örlikon. A new building would be constructed on the site of a former salt depot on Sihlquai, in the immediate vicinity of the college’s administrative offices, containing classrooms and expanding the institution’s range of facilities. Stücheli Architekten won the international competition to design the building that was held by the cantonal building authorities in 1997. With its “Mark” project, the firm succeeded in providing students with a contemporary learning environment and the district with a new landmark.
Right next to the site, the art school designed by Steger und Egender Architekten in 1933 and the technical college designed by Eduard del Fabro and Bruno Gerosa in 1961 join the succession of outstanding buildings that line the river. The project had to take these impressive structures into account.
An L-shaped structure was chosen to ensure that the large construction volume of around 3,000 cubic metres could be optimally integrated with the surroundings. The height of the lower part of the structure is aligned with that of the adjacent main building. The tower, which is also used for public functions, stands six storeys higher and is visible from a long distance. Despite the peripheral location of the building, the height of the tower makes its relationship to the neighbourhood clear.
In a reference to the main building and the nearby art school, the strict spatial grid on which the building is structured is reflected in the façade. Functional infills – prefabricated ceiling, wall and window elements – are seamlessly integrated into the frame and lend the structure a restrained elegance. The subtle design vocabulary is striking only upon second glance and continues in the interior.
The spatial proximity to the main building offers scope for joint use of different infrastructures. The media library and the school office are located on the ground floor, as are the offices of the departmental heads. The four stories above that, where the 43 teaching rooms are located, can be accessed via two staircases at the front and back of the building or by one of the two lifts on the tower side.
The classrooms are arranged in a simple, conventional double-sided layout on either side of a corridor. The areas between the corridor supports that were cast in-situ were fitted with tall, red concrete panels. Wooden classroom doors of the same colour were fitted flush into the gaps between the panels. The smooth curvature of the upper edge of the panels and the sharp angles of the exposed concrete supports convey an impression of differentiated, technically outstanding handling of concrete.
Inside the classrooms the combination of warm-toned exposed concrete and light materials creates an environment that is ideally suited to learning. The familiar atmosphere of the individual classrooms, which is strengthened by the high balustrades, forms a striking contrast to the generous dimensions and breadth of the terrace on the fifth floor.
As the only outdoor space, the terrace is intended to serve the students as an additional recreation area. The red wooden tower designed by Karlsruhe-based artist Daniel Roth lends the building a distinctive, urban flair.
The tower’s six storeys contain two gymnasiums, a weight-training room and a gymnastics room as well as storage areas and locker rooms. The gymnasiums offer a sweeping view of the city and all the technical infrastructure required for larger events.
Mechanical rooms and workshops are housed in the second basement storey, with skylights opening onto the courtyard to provide natural light; the classrooms on the first basement storey have windows facing the Sihl.
The TBZ building has Minergie certification. A water heat pump supported by a gas-fired furnace provides heating and hot water for the 7,000 m2 site.