Circular deep renovation versus demolition with reconstruction: Environmental and financial evaluation to support decision making in the construction sector

• The EU aims for climate neutrality in buildings by 2050. • The EU Pro-GET-onE project improves energy efficiency and safety. • Renovation reduces CO 2 but has seismic safety limits. • Circular reconstruction enhances energy and structural performance. • LCA and LCC support comparisons between renovation and reconstruction in building retrofit. The European Union’s imperative to achieve climate neutrality by 2050 demands specific intervention for existing buildings. The Pro-GET-onE European project, funded by Horizon 2020, contributes to this agenda by focusing on energy efficiency and seismic resilience through innovative technologies tailored for building envelopes. This strategy was tested on a specific pilot case of a student residence in Athens, Greece, on which an exoskeleton in steel was implemented for both increasing volumes and enhancing the energy and seismic performance of the building. This paper presents comprehensive Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) analyses and a circularity assessment of sustainable strategies for deep renovation and sustainable reconstruction using the One Click LCA tool. Focusing on Global Warming Potential (GWP), this study first assesses the environmental impacts associated with five different construction technologies for demolition with reconstruction scenarios; then, it compares the smartest one with the pre-renovation state, deep renovation scenario, and Pro-GET-onE strategy. This study considers factors such as energy consumption, circularity of materials, and economic feasibility by evaluating different costs, including construction, operation, maintenance, and end-of-life. The environmental impact analysis over 50 years reveals that the renovation scenario minimizes CO 2 emissions due to the reduction of energy consumption; however, it does not provide seismic safety. The economic impact analysis indicates that even with a high initial investment, demolition with reconstruction using Glulam and CLT represents the most cost-effective solution over the building’s lifecycle, providing both high energy and structural performance. In contrast, the deep renovation and Pro-GET-onE scenarios entail higher costs but present numerous advantages, such as low service disruption, avoiding residents’ relocation, and smaller time duration. The conclusions of this study highlight the transformative potential of Pro-GET-onE measures in achieving environmental sustainability and decarbonization. This research underscores the importance of LCC and LCA methodologies in evaluating project feasibility and cost-effectiveness, providing valuable insights for policymakers, building owners, and stakeholders. Understanding the long-term economic and environmental implications of construction and renovation projects is crucial for informed decision-making and guiding the building sector toward its energy efficiency and environmental goals.