An updated multi-criteria decision-making method for the sustainable renovation of buildings including environmental, economic and social life-cycle metrics

The ambitious targets of carbon emission reduction set worldwide for the coming years entail the commitment of structural engineers towards the sustainable renovation of existing buildings. The life cycle thinking (LCT) approach offers a holistic perspective for the design of sustainable retrofitting strategies. It envisages the reduction of the environmental impact at all building life cycle phases, while also addressing economic and social issues. Multi-criteria decision-making (MCDM) approaches support the choice of optimal retrofitting solutions, thus being relevant tools for boosting the actual adoption of LCT in current practices. In this study, a previously proposed MCDM approach is enriched with additional LCT-inspired decision parameters (module D beyond-life impacts, environmental payback period, invasiveness), and is then scrutinised and discussed through its application to a case-study building. Four integrated retrofitting scenarios are investigated using state-of-art seismic loss and energy performance assessment methods, including four different types of exoskeletons, made of timber, steel, and concrete. The end-to-end integrated assessment shows that the inclusion of additional LCT-inspired decision criteria effectively favours LCT-based retrofitting interventions over more traditional ones.