Wilhelm Riphahn / SSP AG, WiSo-Hochhaus, Universität zu Köln

The WiSo complex at the University of Cologne, built in 1956–60 according to plans by Wilhelm Riphahn, exemplifies the potential of repurposing existing buildings. 2020–25 the historic building was renovated and transformed into a contemporary learning and working environment. The guiding principle »The double opportunity: the best building material is the existing structure« reflects not only an ecological but also a cultural stance. At the heart of the transformation was the goal of preserving as much of the existing building fabric as possible. Materials such as brick, concrete, steel, natural stone, and wood, as well as parts of the fixed and movable interior fittings, were deliberately reused and integrated into a new usage concept. This strategy follows the principles of sufficiency and circularity and makes a significant contribution to reducing CO2 emissions. At the same time, the building underwent comprehensive technical retrofitting: new building and media technology, optimised insulation standards, high-quality glazing, and a contemporary fire safety and energy concept create a high-performance and sustainable overall system. The conversion is based on three central planning principles: the further development of the building’s DNA, ensuring long-term adaptability, and the GreytoGreen catalogue of measures. In this way, the building’s architectural identity is preserved, while flexible spatial structures and optimised space utilisation meet the requirements of today’s university education. Across more than 10 000 sqm of usable space, approximately 860 modern workspaces and study areas were created for students, researchers, and staff. Particular importance is attached to the intangible dimension: history, atmosphere, and a sense of belonging. The renovated building builds on its past as a defining location for the Faculty of Economics and Social Sciences and brings this legacy into the present. The visible connection between old and new makes the transformation processspatially tangible and strengthens users’ connection to the place.