Trä- och betongstommar i småhus : En jämförelse mellan trä- och betong som byggnadsmaterial med avseeande på LCA och LCC

Sammanfattning

Purpose: Wood and concrete are widely used construction materials with distinct advantages and challenges. Wood, a renewable material, has low carbon emissions, is lightweight, and reduces costs and construction time but requires protection against fire and moisture. Concrete offers strength and fire resistance, making it suitable for durable structures like buildings and bridges, though it has a higher carbon footprint during production. This thesis compares wood and concrete through Life Cycle Analysis (LCA) for environmental impact and Life Cycle Cost Analysis (LCC) for economic feasibility, using One Click LCA software to analyze costs and emissions. Method: This study is based on two methodologies: a literature review and a case study. The literature review is conducted to investigate the properties of both wood and concrete materials. The case study is based on two buildings located in Västra Skälby. Interviews were also included in the case study to provide a deeper discussion. Results: Based on the analysis of these case studies on concrete and wood materials, the wooden house emits 79 tons CO₂e (60 kg CO₂e/m²), while the concrete house emits 133 tons CO₂e (182 kg CO₂e/m²), about 40% more. The main emissions for the concrete house come from phase B6 (54.2%) and A1-A3 (40.4%), highlighting the importance of material selection. One Click LCA estimates the social costs of carbon at 50 EUR per ton of CO₂. The wooden house incurs 3 973 EUR, while the concrete house reaches 6 655 EUR, making it 2 682 EUR higher, emphasizing the need to reduce emissions. Conclusions: Wood is generally a more environmentally friendly alternative to concrete. This is primarily due to wood's lower carbon footprint during production and its ability to store carbon. Life cycle assessments clearly show that wooden buildings emit significantly less carbon dioxide over their lifetime compared to concrete buildings.