In 2018, the construction sector was responsible for 39% of the worldwide energy and process-related carbon dioxide emissions (Global Alliance for Buildings and Construction et al., 2019). This is partly due to the embodied carbon, which represents the carbon emissions related to building construction and material production (LETI, 2020). While zero energy buildings and zero energy renovations start to get the operational carbon down, the circular economy aims to do this by closing material loops and stimulating the reuse of discarded materials in building construction (Ellen McArthur Foundation et al., 2015). Although it is not a new phenomenon, material reuse does require a substantially different approach and is at this point not yet common in the building industry. This is especially true for load-bearing components. This article presents a pilot project for the reuse of discarded timber formwork for the construction of the façade and (load-bearing) substructure of a new house. Through this pilot case and by reflecting on a series of similar cases, it studies the remaining challenges for material reuse but also proposes and assesses redesign strategies that will allow upscaling the reuse of timber formwork. The project shows that although waste, material, and money can be saved by using reclaimed materials, it does complicate the design and construction process and, as such, does not necessarily reduce the total project budget. Moreover, for reuse to become a current practice, new design approaches and collaborations will need to be established. Finally, socio-economic factors must be considered to increase the acceptance of reclaimed materials in new building construction.@en

A “community of knowledge” of representatives of the housing sector in the Netherlands investigated the impact of the behaviour of residents in sustainable housing, both newly constructed and renovated stock. For this, grey scientific data were used, i.e., data and reports from non-university agencies reflecting research commissioned by civil society NGOs and commercial enterprises. The aim was to find perspectives for action (practical “rules of thumb”) to increase the impact of sustainable housing on CO2 reduction and facilitate the implementation of the Dutch national sustainability program. First, a conceptual framework and research model were created to generate the relevant research questions for the sustainable construction sector. An innovative research approach was used where data from academic non-university researchers were enriched by university academic researchers. Experiences with the methodology used are: (a) It implicitly places the many factors that influence sustainable resident behaviour in context; and (b) it makes clear that data from such research can complement university research with useful data from practice, data that are scientifically difficult to use because they are mostly derived from stand-alone case studies. The perspectives for action that were generated are: (a) Sustainable technologies must add new useful functionalities for acceptance; (b) sustainable supply must be tailor-made because households differ and tenants behave differently from homeowners; (c) decision-making about sustainable investments is not only based on financial factors; (d) residents are reluctant to become involved, so it is important that (e) the people representing contractors should be reliable; and (f) people want personalised plans and on-time delivery. Finally, the collected reports turned out to be focused on practice and therefore provided less theoretical information about the rebound effect.@en