Exterior Wall Sustainable Improvement: Comparing different solutions through an LCA

The built environment is currently responsible for nearly 40 percent of global energy- and process-related CO2 emissions. Each building element affects a building's environmental performance through its passive contribution to both operational energy demand and embodied energy and emissions during each life cycle phase. This has led to encourage all stakeholders in the AEC industry value chain to transparently understand where and when carbon emissions are generated and can be minimised. More informed decisions can be made through tools such as life cycle assessment. LCA analyses the environmental impact during the entire life cycle of a product/service/process. Using LCA, the embodied energy of a building (energy consumed during production, construction and replacement of building components) can be calculated in terms of kgCO2eq. This thesis considers the most widely used opaque external envelope solutions in the residential sector: a traditional masonry wall, a CLT wood wall and a drywall. All of these are applied to a case study: a new residential building located in Milan. All solutions were analysed by following the building project and construction phases provided by EN 15978. Each phase, from the product phase, through construction and use to end of life, was analysed and improved in terms of kgCO2 emissions. In order to perform the calculations, material's Environmental Product Declaration (EPD) and OneClick LCA software were used. In conclusion, the thesis aims to highlight how LCA results are key factors in more informed decision making. Effective decisions for the development of low-impact buildings can in fact already be evaluated at the initial design stage.