A twin for the Helvetia tower

As a tribute to the existing high-rise building, Herzog & de Meuron have added a second, almost identical tower. After constructing the newbuild, the existing building was renovated and modernised. This involved a reorganisation of the rooms, an energy-efficient refurbishment and a new façade that perfectly matches the newbuild. A striking feature of the matching towers is on the front façade of both buildings, where large diamond-shaped windows are positioned one above the other.

An auditorium was integrated between the two buildings, the roof of which is supported by a “forest” of 24 columns that each measure twelve metres in height. The transparent building opens invitingly to the St. Alban district and helps to better integrate the Helvetia Campus into the urban landscape. The auditorium also provides access to both office buildings and the approximately 1200 new workstations. The floor-to-ceiling glazing floods the entrance area with plenty of natural light and the projected top-hung windows provide natural ventilation.

The new open-plan office provides a modern work environment with maximum levels of natural light and controlled thermal insulation. The façades on the east and west sides are equipped with an AAC façade made from Schüco AWS 90.SI special profiles. The three-layered construction with active sun shading enables regulation of light in any weather. In the upper floors, continuous glazing with floor-to-ceiling sliding front panels offer fantastic views. While this space is an informal lounge area in the new building, the uppermost floor of the renovated high-rise building houses a publicly accessible café. The optimised use of daylight is part of sustainable energy management, which has also been implemented in the existing building.

In the interest of sustainability, the majority of the existing architecture has been integrated in the new design. The reuse of the existing office tower alone saves more than 80 % of the grey energy in comparison to constructing a completely new building. Emphasis was also placed on the easy dismantling and reuse of the individual components. The new buildings in the first construction phase – the connecting auditorium and the second office tower – were built in accordance with guidelines from the German Sustainable Building Council (DGNB) and the Swiss Sustainable Building Council (SGNI) and awarded “Platinum” level certification. Photovoltaic systems with a surface area of almost 900 m² account for a significant proportion of the electricity required. The energy concept has been supplemented with night-time cooling, as well as highly insulated windows and doors from Schüco.