With its sculptural appearance, the modern and urban CityGate office building in Stuttgart is characterised by strong shapes and clear lines. The special character of the impressive building, which was designed by KSP Jürgen Engel Architekten in Frankfurt, has only a few striking façade details.

The monolithic CityGate is stacked in height like giant toy blocks. In its exposed location at the main railway station, the office complex forms the new starting point for the Stuttgart University Quarter. The eleven-storey high-rise is a striking part of the city and, despite its massiveness, makes sensitive references to neighbouring properties through selectively placed projections and recesses.

The complex is split into two halves by a glazed entrance area, which clearly stands across the entire height of the façade. This vertical recess is designed as a mullion/transom system in one structural glazing building envelope. In contrast to this, a striking design feature of the other façade is the storey-height units with light natural stone cladding. Deep reveals and their colourful accentuation in a powerful red give the façade a three-dimensional depth. Installed on the second level, the Schüco AWS 75.SI aluminium windows with triple insulating glass are positioned as fixed glazing, while floor-to-ceiling ventilation vents are each located laterally behind folded perforated sheet cladding. Together with the red reveals and the precision design of the joints, this folded and punched sheet aluminium also adds to the particularly geometric and three-dimensional effect of the façade. The complex was designed as a reinforced concrete frame construction, where the special construction feature is also the load-bearing reinforced concrete supports in the açade level.

Heating and cooling of the building are ensured through an innovative energy supply concept which integrates ultra-modern heating, cooling and ventilation technology with concrete core activation. CityGate has received the highest possible certification of platinum, in accordance with the German Sustainable Building Council (DBNB) standard.

Words: Bettina Sigmund