Abstract
Modernist housing estates are a significant part of the urban landscape in Europe. Due to their specific urban form and socio-cultural characteristics, transformations of these structures— primarily through the introduction of new development—raise controversy. This article examines the theoretical and practical aspects of infill development in housing estates, using the example of Ursynów Północny in Warsaw. It demonstrates that while authorities aim for functional diversification and real-estate developers pursue economic objectives, residents often resist new construction, fearing a decline in their quality of life. Housing cooperatives, acting as intermediaries in the transformation process, view new developments as an opportunity to generate funds for modernizing the housing stock and shared spaces. New developments can address structural challenges cities and estates face, such as the lack of affordable housing, the demand for new services, or the phenomenon of studentification. The study emphasizes the importance of the ‘critical reconstruction’ of the urban reality, which integrates political, social, and economic objectives.