Jämförelse av hållbarhets- och miljöaspekter av trä- och betonghusbyggande

Sammanfattning: Environmentally friendly and sustainable construction is an increasingly important matter worldwide and in Sweden. The growing population, coupled with rising demands for living standards, has led to a greater use of materials and goods, resulting in increased environmental problems. In Sweden, the construction sector accounts for approximately 21 percent of total greenhouse gas emissions, excluding emissions from imports, amounting to around 15.9 million tonnes of carbon dioxide equivalents since 2020 (Boverket, 2023). These numbers emphasize the need to focus on reducing environmental impact and promoting sustainability within the construction industry. Currently, wood and concrete are the two most commonly used materials in the construction industry. Wood is an incredible carbon sink. In the ecological cycle, materials are naturally produced as carbon dioxide is absorbed from the atmosphere and carbon becomes bound in glucose molecules. This characteristic makes wood highly valuable for construction purposes since the carbon remains stored within the wood for an extended period. On the other hand, the use of concrete traces back to 500 BC during the Roman Empire. Concrete is a durable material with an extensive lifespan, and unlike other materials, it requires minimal operating and maintenance efforts. Due to these numerous advantages, concrete is also a favored building component in the construction industry. As environmental and sustainability considerations are crucial for the future, and the choice of building materials plays a decisive role in these aspects, this study aims to investigate and gain a deeper understanding of the life cycle analysis (LCA) for both materials in stages A1-5. The objective is to analyze and determine which material, wood or concrete, is more suitable as a building material from an environmental and sustainability standpoint. The investigation involves comparing and analyzing two exterior walls: one with a wooden frame and the other with a concrete frame, using the LCA calculation program (One Click LCA). The functional unit for this study is kilograms of carbon dioxide equivalents per square meter of floor area (kg CO2e /m2 Atemp). The study's results were obtained through a combination of literature review and the use of the One Click LCA calculation program. The literature review provided additional information about concrete and wood as building materials, contributing to a comprehensive understanding of their respective properties, strengths, and weaknesses.The calculations from One Click LCA clearly demonstrate that the concrete frame emits significantly more carbon dioxide than the wooden frame. The total carbon dioxide emissions from the concrete wall are 12,150 kg kg CO2e /m2 Atemp, nearly double the emissions of the wooden wall, which amount to 6,010 kg kg CO2e /m2 Atemp.