The former supermarket in the Rosenberg residential area in Winterthur was vacant for a number of years after a shopping center had opened in its vicinity. The building code only offered little flexibility for floor area increase and use conversion of the flat roof commercial building completed in 1961 into a multi-family residential structure. Despite this fact, the architects and their project developer subsidiary DN2M created five housing units with 140 to 180 m² within the existing building envelope and a setback rooftop addition comprised of prefabricated wood panel construction.