Life cycle assessment comparison of two residential buildings using wood and concrete in Sweden : A Global Warming Potential comparison between material choices within Attacus Stomsystem AB chain of production with considerations for temporal dynamics

Abstract: Using the case study of a six-floor residential building with 4254 m2 living area and its supply chains, service life and disposal in the Swedish context, a conventional life cycle assessment focused on Global Warming Potential was carried out. The assessment is incomplete because sections B1-B5 were not taken into consideration. A Time Adjusted Warming Potential was also calculated from the conventional results to address the dynamics in the long service life of wooden and concrete buildings. The results are 358 kg CO2 eq/m2 and 175 kg CO2 eq/m2 for concrete and wood, respectively. Of the alternatives analyzed, both using slag concrete and combining the materials in hybrid buildings were shown to have significant reduction potential. The dynamic analysis did not change the overarching results because they strengthened the existing differences. Temporal recalculations were responsible for substantial difference, between 11% (full life cycle for concrete building) and 55% (post-use carbonation) in the categories which apply. This thesis therefore argues for these dynamic issues to be further addressed in the field of LCA methodology. Taking time of emission into consideration leads significant difference in the results particularly in products which have longer life cycles such as the construction industry. These should be addressed in a systematic way.