Environmental impact assessment of refurbishment versus new construction: a multi-category life cycle analysis of building projects

Despite the pressing need for sustainable construction practices, the building industry remains a significant contributor to environmental degradation across multiple impact categories. In response, there is increasing pressure to transition from a linear model to one guided by circular economy (CE) principles. However, research integrating circularity scenarios with comprehensive environmental assessment in building projects is notably scarce. This study addresses this gap by focusing on the potential of the 4th strategy of the 10R circularity strategy framework - refurbishment - to reduce environmental impacts in building projects. This study expands on previous research by considering varying building geometries. This allows for a more comprehensive comparison between new construction and refurbishment across multiple scenarios in Iran. The findings from a life cycle assessment (LCA) in this case study suggest that refurbishment could reduce environmental impacts by 50 %–60 % across all seven environmental impact categories including global warming potential, ozone depletion, acidification, eutrophication, photochemical ozone creation, abiotic resource depletion, and abiotic resource depletion. This paper advances theoretical understanding by rigorously quantifying environmental impacts at various stages and for major contributing materials, outlining potential avenues for impact reduction and future research. It provides one of the first comparative analyses of refurbishment versus new construction, incorporating diverse geometries and multiple scenarios for existing buildings. For practitioners, this study serves as a reference for informed decision-making, offering predictive insights into the benefits of adopting refurbishment over new construction in terms of comprehensive environmental performance.