A study of potential climate impacts from maintenance and replacements in timber buildings : From a lifecycle perspective

Abstract: The building sector contributes to a large part of the total emissions of greenhouse gases, which demands for increased sustainability in all phases of a buildings’ lifecycle. Choices of building materials and the respective required maintenance and replacements are becoming more important if further reductions of climate impacts should be obtained. Folkhem is a Swedish construction company who constructs multi-storey buildings made of wood. The company has shown interest in developing knowledge about how the selection of building materials effects the impacts on climate, the extent of necessary maintenance and replacement work as well as economic consequences. The aim of this master thesis was to evaluate the potential climate impacts and costs for different scenarios of maintenance and replacements of selected exterior building components for Folkhem’s planned building in Stadshagen, in Stockholm. The façade, roof, windows and balconies have been in focus. To fulfill the aim of this study, life cycle assessment and a simplified cost analysis have been carried out. With the basis of the results from this study, recommendations of building materials for the chosen building components in Folkhem’s planned building have been stated. A façade made of pine impregnated with boiled linseed oil is recommended as façade cladding, and OrganoWood is recommended for the balcony decking. Folkhem planned to use wooden windows, but it is recommended that these are substituted to aluminum coated wooden windows. No recommendation could be provided for the roof from this study. The following conclusions have been made; More attention should be payed to the phases of maintenance and replacement when carrying out LCAs for timber buildings, since general assumptions could be misleading. The origin of the building materials could have a significant climate impact if several replacements need to be performed, since this includes a large number of transports of materials. Different building materials or building components have different lifespans and needs for maintenance. To reduce costs and potential climate impacts, long lifespans with little need for maintenance are desired. Planning for a specific lifespan of the building and the required maintenance and replacements may contribute to reduce the potential climate impacts. Maintenance is recommended for timber buildings, since this could reduce the need for replacements, which could reduce the potential climate impacts. LCA can be a useful tool for Folkhem to plan for maintenance and replacements of their timber buildings if improvements are performed regarding LCA data quality. LCA can provide guidance for Folkhem to choose sustainable building materials, with regards to maintenance and replacements at an early stage in the design process. A future study could be to perform a more detailed LCA of the materials and products that required assumptions in this study, for instance the surface treatments for maintenance. A more detailed LCA of all maintenance that should be conducted in a building could be of interest as well, and to investigate the impacts from excluded processes in this study. Alternative building materials for the exterior building components could be evaluated as well as different percentages of painting area. More impact categories than climate change could also be evaluated. Impacts from the building lifecycle phases of repair and refurbishment could also be interesting to evaluate in order to receive an overview of the total potential climate impacts and costs from all parts of the lifecycle of a building. Another approach could be to investigate if maintenance and replacement are carried out as described from technical literature and manufacturers in reality. Finally, a more thorough cost analysis could be carried out, evaluating how a housing society would be affected from costs from maintenance and replacement.