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

The world’s population alongside the general consumption and use of natural resources hasgrown immensely during the past decade. The construction sector is today one of the industriesthat has the highest impact on the environment. Therefore, the current linear economy has to bemoved towards a circular economy which aims for material- and resource efficiency. The concept of reverse logistics for reuse of construction material and the need for collaboration hasbeen identified as key areas for transitioning to a circular economy and thus has a decisive rolein reducing the construction waste. However, due to the construction industry beingfragmented, a lack of collaboration amongst real estate developers and other market actors hasbeen identified as a barrier for successfully implementing the reuse of construction materials.Furthermore, the real estate developer is seen as a key actor to utilise the potential of the reuseof construction materials by creating incentives and collaborations with other actors involved. The aim of this paper was therefore to investigate different actor’s perspectives in the realestate- and construction sector regarding reuse of construction materials and what the keybarriers and incentives are for them to implement it. Furthermore, by gaining an understandingof each actor's perspective the aim was to create a framework model for how a real estatedeveloper can achieve a strategic collaboration with different actors to make the process ofreusing construction materials in tenant adaptation projects more efficient. This was achievedby interviewing key actors within the real estate- and construction industry in order to get anoverall perspective on their views. Furthermore, a survey was conducted to obtain anunderstanding of the tenants view on having reused construction materials in their facilities. The results indicated that the main barriers were; a lack of incentives, lack of logistics &recovery facilities, an established procedure for quality assuring the material & warranty issuesas well as the tenants’ perception of it. Furthermore, the results show that the real estatedeveloper can create different types of incentives for the tenants and involved actors in order tofacilitate the implementation of material reuse and an established collaboration. Lastly, aframework model was presented to demonstrate how a real estate developer can collaboratewith different actors in order to get a deeper understanding of the dynamics of a potentialcollaboration. / Världens befolkning har i samband med den generella konsumtionen samt vår användning av naturresurserna ökat avsevärt det senaste decenniet. Bygg- och fastighetssektorn är idag en av de industrier som har störst påverkan på vår miljö. Därav behövs en skiftning från den linjäraekonomin till en cirkulär ekonomi som grundar sig i material- och resurseffektivisering.Konceptet omvänd logistik för ett ökat återbruk av byggmaterial och behovet av samarbete har identifierats som viktiga verktyg för skiftet mot en cirkulär ekonomi och därmed en minimeringav byggavfall. Då byggbranschen idag är fragmenterad har bristen på samarbete mellan fastighetsägare och andra aktörer identifierats som en utmaning för att implementera återbrukav byggmaterial med framgång. Vidare ses fastighetsägare som en huvudaktör som kan utnyttja potentialen som finns kring återbruk av byggmaterial genom att skapa incitament ochsamarbeten med andra involverade aktörer. Därför var syftet med denna rapport att utreda olika aktörers perspektiv på återbruk avbyggmaterial inom bygg- och fastighetssektorn samt vad de främsta barriärer och incitament ärför att de ska implementera det. Vidare, genom att få en förståelse för samtliga aktörersperspektiv var målet att skapa en modell för hur fastighetsägarna kan uppnå ett strategiskt samarbete med olika aktörer för att effektivisera processen av återbruk av byggmaterial vid enhyresgästsanpassning. Detta uppnåddes genom att intervjua huvudaktörer inom bygg- och fastighetssektorn. Vidare gjordes en enkät för att erhålla en förståelse för hyresgästerna syn på att ha återbrukatbyggmaterial i deras lokaler.