Redefining the concept of sustainable renovation of buildings: State of the art and an LCT-based design framework

The sustainable renovation of existing buildings is commonly intended as the upgrade of constructions by implementing green technologies and eco-friendly materials. More recently, the concept has been broadened to include all the pillars of sustainability (environmental, economic, and social aspects); however, it rarely en- compasses structural safety, with the result that buildings renovated to be ‘more sustainable’ may remain structurally unsafe and even collapse in case of earthquake. Recent studies proposed new frameworks to include all these sustainability aspects in the building retrofit; however, these may still fail in the aim of minimizing impacts along the building life cycle and overcoming the barriers to the renovation. In this paper, a critical review of these existing methods for sustainable retrofit is firstly carried out, and the major research needs are highlighted. Trying to overcome these issues, the comprehensive concept of Sustainable Building Renovation (SBR) is introduced, addressing Life Cycle Thinking and holistic perspectives in each phase of the design. Then, an innovative SBR design framework, adopting Multi-Criteria Decision Making (MCDM) methods, a multi- disciplinary Performance-Based Design (PBD) approach, and expanded Life Cycle analyses, is proposed and applied to a typical European building to design and select the most sustainable retrofit option.