Energy retrofits of residential buildings in Brussels: What impacts on stocks and material flows?

One of European Union’s main goals is to promote efficient resource management via conservation and preservation of these natural resources. Waste reduction and recovery improvements are key components as well. Moreover, within the context of present energy efficiency, the renovation of the old and energy-consuming housing stock has become a major issue. Although the renovation process generates energy gains during the operation phase of the building, it also leads to resource consumption and waste production that are rarely taken into account in the design process. Therefore, the initiatives essentially based on energy efficiency alone have to be extended in order to incorporate the future value of recyclable and recoverable materials. In this way, the research proposal is to consider buildings as a bank of materials that could constitute local resources on a medium or long-term basis? Considering the context and issues mentioned above, the present contribution aims to answer the followed question: what impact will the energy-retrofit of buildings have on material stocks and flows? The data in this field is currently non-existent or incomplete. Our proposal is to analyse case studies in terms of intervention trends of sustainable retrofit on the one hand - considering demolition and insulation - and in terms of material balances on the other. Particularly, we considered the energy retrofit operation in metabolic terms: the purpose is to identify and quantify the material stocks and flows created before, during, and after the renovation process. Because it is one of the most important elements of the building that has to be upgraded to achieve energy efficiency, this contribution focused on the building envelope.