Building vertical extensions and increasing housing stock in cities: Review of selected European research

This paper presents the issue of the vertical extension of buildings, mainly residential, as an element of su-stainable housing policy of European cities. This type of construction project allows for the acquisition ofadditional residential space, using the existing technical infrastructure, and also not deepening the effect ofurban sprawl. Vertical extensions allow for the construction of new apartments in urban areas, being one ofthe forms of densifying the existing buildings. The study reviews research on the subject of vertical buildingextensions, trying to answer the research questions posed: how and with the use of which building analysistools it is possible to improve the process of vertical extension, so that it can become an actual element of thehousing policy of cities. Three original studies were selected for the analysis: from Germany, Belgium andEngland, which met the criteria set by this study, presenting a universal scheme of action for vertical exten-sions, not treating them as incidental, individual construction intervention, and treating vertical extensions asan element of systemic action for the acquisition of new apartments. The selected studies are carried out incountries economically and culturally similar to Poland, which was also one of the selection criteria. The studyis also to be a voice in the discussion on the possibility of the vertical extension of residential buildings as anelement of housing policy in Poland.