Renovation of the façade of an 18-storey social housing tower with 380 flats that remain occupied during the works. In order to meet the passive house standard, all flats are equipped with a completely new ventilation system. For the same reason, the existing balconies are being demolished and replaced by new prefabricated concrete balconies. The windows are also replaced with aluminium frames with thermal breaks and energy-efficient glazing. The outer shell is stripped down to the concrete structure and insulated. Despite this extensive work, the building retains its original appearance.