Sustainability Assessment of a Wooden Multi-Storey Building Compared with an Equivalent Reinforced Concrete Alternative Using ToSIA: Finnish Perspective

The aim of this study was to conduct a sustainability impact assessment (SIA) on a wooden multi-storey building and compare this to an equivalent reinforced concrete building using ToSIA (Tool for Sustainability Impact Assessment). The SIA considered the material flows and processes along the respective supply chains in Finland and included environmental, economic, and social indicators. The greenhouse gas savings of various wood-based materials of the buildings were also compared with concrete elements. The boundary of the quantitative analysis was cradle-to-construction site and included the structural support system of the building. Primary data was collected from the material supply chain and manufacturing facilities and were used to develop the life cycle inventory database. Secondary data were also referenced for the selected indicators. The results indicated that the wood frame structure provided greater environmental benefits, being responsible for only one-third of the greenhouse gas emissions and two-thirds of the non-renewable energy consumption during building material sourcing to the construction site gate, compared to the reinforced concrete alternative. In terms of socioeconomic sustainability, the reinforced concrete alternative had higher production costs, but a lower labour intensity than wood. It was also found that non-fatal accidents occurred more often in the concrete supply chain, especially at the manufacturing facility, indicating that work safety was higher in the wood-alternative. In addition, the avoided greenhouse gas emission calculation showed that 159 kgCO 2 m –2 could end-of-life scenarios and the cascading use of wood to find further greenhouse gas emissions savings.