Measuring building circularity through materials, processes and impacts: an evaluation framework for architecture integrating reused, bio-based and recycled components

In line with circular bioeconomy goals, this research focuses on circular materials—reused, bio-based (including waste-derived ones) and recycled—as a strategic solution to simultaneously cut Embodied Carbon and material resource uptake in buildings. The research develops a methodology for early, rapid assessment of circular materials’ contribution to cutting climate-altering emissions and material consumption, supporting architects during the initial design stage, where strategic choices are most impactful. Multiple case studies of buildings employing 12 circular design strategies and different materials were analysed, of which 10 are presented here, mapping approaches and material mixes. In parallel, by analysing 15 existing circularity and sustainability evaluation frameworks at the building and product level, screening 80 relevant indicators and integrating specific ones, the research develops a set of eight KPIs enabling designers to assess alternative combinations of reused, bio-based and recycled building materials from the early design stage. Validated on three case studies, the KPIs proved sensitive in capturing the diversity of circular material strategies by measuring circular material origin, local materials, disassemblability, material and Embodied Carbon intensity, with the latter proving particularly effective in cross-measuring the impacts of material choices. The research thus provides operational support for rapid comparative assessments guiding design decisions during early stages, focusing on materials, processes and relative impacts.