Climate and economic implications of structure and façade materials on a building's life cycle performance : A case study of a multi-family building in Sweden

Abstract: This study has been conducted in cooperation with OBOS Kärnhem. The objective of the study is to assess environmental impacts from different structural and facade materials to find a configuration with the lowest impact, and to assess the economic implications of different structural and façade materials. The study is conducted on a case study building planned in Linköping, Sweden. The methods that were used are the life cycle assessment (LCA) and life cycle cost (LCC) methods. Cross-laminated timber and concrete were chosen as the 2 structural materials to investigate, and sheet metal, cut slate, and wood paneling were chosen as the façade materials to investigate. The goal and scope were specified. The goal of the LCA was to analyze the climate implications of different structural and facade materials on a building’s environmental performance, while the scope was to compare the environmental impacts, specifically global warming potential, of six scenarios over a lifetime of 80 years. Later, a life cycle inventory of the materials was conducted, and the life cycle inventory was assessed. Finally, the life cycle interpretation was carried out to analyze and interpret the results. For the LCC, costs were calculated for materials and energy use and applied to the case study building. The analyses of results show that the wooden building scenarios have significantly low environmental impacts when compared with concrete buildings. The analyses of the results also show that the buildings constructed with cast-in-situ concrete have lower life cycle costs when compared with buildings constructed with cross-laminated timber. This study concludes that structural material choices affect the environmental performance of a building significantly. Facade material choices also affect the environmental performance, however much less significantly. This study also shows that, within these specific system boundaries, the most impactful life cycle stage for the wood structure building scenarios is the operational phase B6, while the most impactful life cycle stage for the concrete structure building scenarios is the material production stage A1-A3. This study further concludes that while cross-laminated timber buildings have a lower carbon footprint than concrete structure buildings, they currently cost significantly more to build. This highlights the discrepancies between the changes and choices that are required to reach the climate and sustainable development goals, and what is economically viable.