ENVIRONMENTAL CONSEQUENCES OF REFURBISHMENT VERSUS DEMOLITION AND RECONSTRUCTION: A COMPARATIVE LIFE CYCLE ASSESSMENT OF AN ITALIAN CASE STUDY

ABSTRACT

In the building sector, new standards for energy efficiency are reducing the energy consumption and the carbon emissions for building operation to nearly zero. As a result, the greenhouse gas emissions and related environmental impacts from materials production, and especially insulation, are becoming key factors. In the near future, most of the building stock is expected to be refurbished and a great amount of construction materials will be consequently required. A relevant share of waste is generated from building construction and demolition and limiting the volume is a priority of the EU community. In this work the renovation of industrial buildings in a dismissed area located in Lecco, Italy, was considered as a case study. Five alternative construction systems (EPS, WOOD, ROCK, PU, HEMP) for renovating the building envelopes were assumed, and a life cycle assessment (LCA) adopted in order to measure the environmental impact of each alternative. The results were compared with a scenario which included demolition and reconstruction of a similar building with the same net volume and thermal resistance. The results showed that timber and concrete are the most environmentally friendly materials to rebuild the structures in case of demolition, contrary to steel which leads generally to higher environmental impacts, except land use. In general, EPS, WOOD and HEMP technological alternatives accounted for the highest scores, both in terms of burdens on the ecosystems and on depletion of resources, while ROCK accounted for the lowest scores. Finally, refurbishment scenarios generally accounted for a lower global warming potential (GWP) even if demolition, waste treatment and the benefit from recycling/reuse are taken into account.