Basel in Switzerland is known for its outstanding architecture. In addition to the medieval old town, there are heritage buildings from the industrial era and numerous post-war modernist buildings, including high-rise buildings from the period between 1950 and 1970. One of the high-rise buildings typical of this period is home to the headquarters of the insurance company Helvetia. It was built between 1954 and 1956.
In addition to the two high-rise buildings (the old and the new) and the auditorium, the overall project for the new Helvetia Campus also includes the redesign of the green area on the Helvetia site, as well as the refurbishment and extension of another administrative building to the south.
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Identical design
As somewhat of a tribute, Herzog & de Meuron have added a second, almost identical tower next to the existing tower block. After constructing the newbuild, the existing high-rise building was renovated and modernised. In addition to the reorganisation of the rooms and the energy-efficient renovation, the existing building was given a new facade that perfectly matches the newbuild. A particularly special feature of the matching towers is on the front facade of both buildings, where large diamond-shaped windows are positioned one above the other.
An auditorium was constructed between the two buildings. The roof is supported by a “forest” of 24 twelve-metre columns. This transparent building opens out invitingly to the St. Alban district and helps to better integrate the Helvetia Campus into the urban fabric. The auditorium also provides access to both office buildings and their 1200 new workstations. The floor-to-ceiling glazing floods the entrance area with plenty of natural light and numerous projected top-hung windows provide natural ventilation.
Plenty of natural daylight
The new office environments are designed as open spaces. In order to ensure a pleasant and modern working environment, maximum daylight was required while also reliably controlling solar heat gain. The east and west-facing facade areas were therefore implemented using an AAC facade, which is constructed from special profiles based on Schüco AWS 90.SI. The special three-layer composition consists of an outer pane, active sun shading and insulating glazing on the inside, which allow sun shading to be controlled independently of wind and temperature.
In the upper floors under the flat roofs, continuous glazing with floor-to-ceiling sliding front panels offer a fantastic view. In this upper area of the newbuild, employees will find informal lounge areas. In the renovated tower, this floor is used as a café, which is also open to the public.
All part of a larger sustainability concept
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The improved use of daylight is part of the introduction of sustainable energy management, which has also been applied 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 percent of the grey energy that would have been required to construct an equivalent newbuild.
At the same time, emphasis was placed on the easy dismantling and reuse of the individual components, such as the facades of the towers. Both of the newbuilds 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. Large-scale photovoltaic systems that cover almost 900 square metres across all three roofs account for a significant proportion of the electricity required.
Night-time cooling was also introduced as a way of utilising sustainable resources to cool the building. Highly insulated Schüco AWS 70.HI aluminium windows were used for this. Furthermore, the large-scale, highly insulated Schüco ADS 75 HD.HI aluminium doors support the energy concept of the building.
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