The former telecommunications tower has dominated the Bielefeld cityscape since the 1970s. Following its comprehensive modernisation, the building now has a new name and a new appearance: after the extensive revitalisation project, including a redesign of the façade, it now has a fresh new look as “H1”. Goldbeck took on the roles of client, investor, main contractor and planner all at the same time.
| Type of Building | Districts and mixed use buildings |
| Product areas | Windows Doors Facades Solar shading |
| Schüco Systems | AWS 90.SI+ FWS 60.SI ADS 80 FR 30 |
| Features | Refurbishment DGNB |
| Location | Bielefeld, Germany |
| Completion | 2024 |
| Architects | Goldbeck |
| Specialist company | Goldbeck |
| Picture credits | © GOLDBECK GmbH / Christian Eblenkamp |
Before planning could begin, fundamental decisions had to be made with regard to the future use of the property. As part of the analysis of the existing building, the condition of the building was assessed and the limitations were identified. Demolition and reconstruction were out of the question for both economic and regulatory reasons, as rebuilding with a height of 74.26 metres would not have been feasible due to building regulations. In addition, the high-quality reinforced concrete structure, which could be preserved without significantly contributing to pollution levels, made a convincing argument for renovation. After examining different usage concepts, the decision was made to create a multi-tenant office building while simultaneously revitalising the property to meet new building standards.
The façade was implemented using the AWS 90.SI+ window. The new façade echoes the horizontal structure of the previous building but offers significantly larger window areas and emphasises the horizontal lines using narrow cassette cladding with rounded corners. Together with the larger window proportions, this helps to create a seamless façade appearance that allows plenty of light into the building. In the sill area, a mullion/transom construction based on the Schüco FWS 60.SI system ensures maximum transparency. The bright white cassette cladding elegantly curves around the façade and gives the main entrance on the ground floor an eye-catching and welcoming appearance.
While the high-rise building was being gutted floor by floor and the old façade was being dismantled from top to bottom using mast climbing work platforms, structural planning for the new façade was getting underway. A 3D laser scan offered a precise overview of the not insignificant differences between the measurement reference point and the unit joint of the old façade. It also provided planners with valuable data that was used to define a uniform height for the window units and to compensate for tolerances from the existing building shell through the substructure.
The new window façade was designed according to the principle of systematised construction units, which means as many identical units as possible were used in as few different positions as possible. Apart from the sill, there are only seven positions for all 1080 window units of the high-rise building and three positions for the 1140 cassette units.
A 250 mm wide ventilation flap in the window units enables independent ventilation on every floor. This was subjected to a high-rise building test at the Schüco Technology Center, as high wind speeds require special sealing measures. For the external sun shading, automatically controlled window awnings with high wind resistance were used. In addition, downdraught issues meant that a reinforced substructure for the cassette units was required in the sill level.
With a Uw value of 0.78 W/m²K and 20 cm of mineral wool insulation (WLS 035), the new façade meets the latest standards in energy efficiency and significantly contributes to reducing the operating costs of the high-rise building. From a design perspective, the old appearance and feel of the building has been successfully reinterpreted without having to retain its monotonous grid aesthetic.
