Overview and main findings for the austrian case study

Abstract

As part of a project investigating in the potential greenhouse gas mitigation effect of the increased use and production of mass timber worldwide, a comparative study was carried out to show the potential benefit of mass timber use in buildings in central Europe. After designing a mass timber building functionally equivalent to an existing conventional building, cradle to grave life cycle assessments (LCA) were calculated. The reference is an eight-story building with mixed use in Vienna, originally built in reinforced concrete. Global Warming Potential (GWP) is defined as the central parameter of interest. Calculated life cycle phases are A1–A3 (resource to production), A4 and A5 (transport to site and construction, respectively), B4 (replacement in the use phase), and C1–C4 (End of Life), as well as D (benefits and loads beyond the building life). It can be shown that the total mass of the timber building is 47% lower than of the concrete building. Considering life cycle phases A1 to A5, the timber building shows 18% less embodied carbon. Taking the whole building life cycle and the operational energy use (B6) into account, differences in GWP are much lower, as the heating system, though equipped with high efficiency and clean Austrian electricity grid mix, has much higher impact than the other phases.