The historic city centre of Constance is characterized by its compactness and homogeneity. The project incorporates the historical formation of the surrounding buildings with its 30m long plots and projects this format into the 10m wide front. The mixed use building completes the city block towards the high street; the courtyard provides daylight from the south where an arcade offers flexible external areas within the otherwise dense historic city centre. The main elevation responds to the punctuated façades of the neighbour- ing medieval buildings and the directional change of those. An intersection of these two directions emphasizes the perspective in a sculptural manner. A grid of horizontal and vertical concrete columns are spatially distorted thus reinforcing the depth of the façade.Zero waste The building is constructed of lightweight fair faced concrete. The material can be seen everywhere thus giving an impression of a fluid transition between outside and inside. The solid 50cm thick walls are entirely con- structed of lightweight concrete, avoiding the use of additional thermal insulation or membranes. They reflect medieval tech- niques of building solid walls which perform as a weather membrane and thermal mass storage by using a mesh of timber, straw and clay. The lightweight concrete wall performs in a similar way and can be easily demolished. The material is completely recyclable and achieves zero waste require- ments.The building extends along the party wall of the 30m deep site where an elongated area in the middle connects the front and the rear of the building. A vis-à-vis situation is created within each apartment.The staircase forms the only communal area of the building. The open stair and landings invite the residents to meet. The expressive surfaces mediate between public and private areas, the three dimen- sional external facade and the plain and open internal spaces.