Jämförelse av prefabricerade bjälklagssystem ur ett hållbarhets- och ekonomiskt perspektiv : Comparison of prefabricated floor systems from a sustainability and economic perspective

As the construction and real estate sectors face increasing demands for sustainability, the choice of materials has become increasingly important in reducing climate impact and improving cost efficiency in construction projects. This thesis aims to compare two prefabricated floor systems: hollow-core concrete slabs with accompanying steel beams (floor system 1), and TT-panels made of cross-laminated timber (CLT) and glulam with accompanying glulam beams (floor system 2), from both a sustainability and economic perspective. The work included a life cycle assessment (LCA), an embodied energy calculation, and a cost estimate for each floor system. A five-story building was used as a reference project, with one floor (620 sqm) being analyzed. The LCAs were conducted using the software One Click LCA, and the cost calculations were carried out in Bidcon. The results showed that the TT-panels had significantly lower climate impact, with 35 950 kg CO₂-equivalents and 111 000 MJ less embodied energy compared to the hollow-core slab. At the same time, the cost difference between the systems was marginal, only 616 SEK per floor. Favoring the timber-based system, the TT-panels. The study shows that TT-panels in timber are not only a more environmentally friendly option but also an economically competitive alternative. This makes timber structures a strong contender in the design of sustainable buildings. However, the choice of floor system should always be based on a comprehensive assessment, where acoustic requirements, fire safety, technical conditions, and the specific needs of the project are also considered.