Abstract

The primary goal of this dissertation was to investigate the contrasting approaches of refurbishment and replacement concerning modernist housing estates, amidst the challenges of urban densification and the imperative for heightened sustainability. The study’s findings shed light on which policy yields greater environmental benefits, offering insights into the potential role and the position of modernist housing estates in future urban landscapes. Building upon established Refurbish vs. Replace evaluation framework, this research extends the environmental component by integrating densification and sustainability factors as the control mechanisms into the comparison system boundary.

Central to the methodology is Life Cycle Assessment (LCA), augmented with additional preparatory steps and calibrated to align with global guidelines and practices. These steps involved compiling design norms, developing building materialization and urban densification concepts, ensuring that competing refurbishment and replacement scenarios reflect contemporary sustainability practices. Through incremental increases in built volume, the methodology sought to assess the carbon neutrality of proposed solutions at various control points, unveiling the maximum energyneutral construction limits achievable with current state-of-the-art technological advancements. These control points also served as referent baselines for the comprehensive Life Cycle Assessment (LCA) of the two respective entry scenarios. Methodology was tested using two denominated approaches for creating scenarios (retention vs. demolition) on an exemplary plot in the Nordweststadt housing estate in Frankfurt. However, through specific attitudes towards shaping the geometry and presenting the output, the findings can be extrapolated to encompass the entire modernist housing stock in Germany.

Results have shown the prevalence of the refurbishment option at all analyzed density points. A sensitivity analysis, considering expected reductions in operational and embodied carbon emissions and depicting a hypothetical situation of a completely decarbonized grid post-2050, further underscores the refurbishment’s superiority and emphasizes the importance of minimizing future embodied energy expenditures