In an era where global sustainability and reduced carbon emissions are central challenges, awareness of climate impact and sustainable construction methods within the construction industry has increased. This study addresses the question of fictitious replacing traditional steel columns with cross-laminated timber (CLT) as the load-bearing structure in the outer walls of an existing building. Additionally, the existing building will fictitious be extended with additional floors to gain a deeper understanding of whether the use of CLT is a potential solution to reduce the sector's ecological footprint.

The aim of the study is to evaluate the potential benefits of replacing steel columns with load bearing CLT walls in multi-family houses. The three aspects to be analyzed are the total carbon emissions of the outer wall in the manufacturing process depending on floor height, the total material cost of the wall depending on floor height, and the U-value of the wall construction depending on floor height. Through these three questions, the study aims to contribute to a deeper understanding of CLT's potential role as a sustainable material within the Swedish construction industry.

The research questions were analyzed by calculating the dimensions of the outer wall construction for each floor height following Eurocode’s guidelines and using Excel for flexibility in adjusting building parameters. The carbon emissions of the outer wall were analyzed by obtaining product-specific Environmental Product Declarations (EPDs) and analyzing stages A1 to A3. Material costs were analyzed using the Bidcon software program. The U-value is calculated and analyzed according to Eurocode’s guidelines, with Excel used for calculations.

The results indicate that CLT generally outperforms steel in terms of carbon emissions and cost-effectiveness, especially in taller buildings. Differences are negligible in lower buildings but become significant as height increases. The CLT construction consistently demonstrates better thermal performance across all building heights. The study's findings underscore the importance of well-informed material choices to create economically and ecologically sustainable buildings.