Introduction – The construction industry emits large amounts of greenhouse gases through waste generated from the construction and civil engineering sector. To reduce these emissions, measures must be taken. The aim of this study is to investigate the reuse of building materials in the construction industry and the improvements that can be made to increase reuse.

Method – The study is of a qualitative nature and distinguishes a more in-depth methodological approach that goes deeper in its interpretation. The different research methods used are literature review and interviews to obtain an overall picture of the problem area.

Results – The results show that it is difficult to reuse building materials due to their quality, time-consuming process, and high costs. There is a lack of knowledge in the construction industry that hinders the reuse process. Windows and doors are often reused in demolition projects, and waste from new construction ends up in recycling stations.

Analysis – Reuse of building materials reduces waste and the need for new resources to manufacture new materials. The choice of material is crucial, and the use of environmentally friendly materials that are easy to reuse is often preferred. One challenge is finding storage space for dismantled materials, as a lack of storage space can lead to materials being sent to recycling stations. Another challenge is ensuring that reused materials meet the same quality standards as new materials. The construction industry is conservative, and actors prefer to work in a traditional way, which limits the use of reused materials. There are currently no laws and regulations regarding the reuse of building materials. Good communication and willingness to work with reused building materials are crucial for successful projects.

Discussion – Since the study includes both literature studies and semi-structured interviews, it has contributed to comparing the results and thereby increasing the study's credibility. To increase the reliability of the study, seven respondents with at least 5 years of experience in the construction industry have been interviewed. Significant effort has been put into the selection of interview questions to avoid misunderstandings and to avoid steering the interviewees' responses. The study's initial focus was on wood as a building material, but due to a lack of knowledge about this material and not all companies working with wood, it has been chosen to write more generally about building materials. This led to the purpose and research questions of the work being adjusted after the collection of empirical data.

Keywords – Reuse, recycling, circular process, waste hierarchy, opportunities, challenges, building materials, circular economy