In recent years, “circular economy” has become a buzzword in building construction to confront sustainability issues caused by the climate and resource crises. City governments develop strategies to become more circular by reusing buildings and building materials and producing less waste. Architectural offices focus on designing buildings with deconstruction in mind. Secondhand material markets collect, make inventories and mediate building materials saved from being thrown to the landfill. However, reusing building materials is still a niche phenomenon in the overall construction industry, mainly because of the high labour costs involved in deconstruction and the relative cheapness of new resources, but also due to the complicated logistics of shifting materials from demolition to construction site. This workshop took place at University of Fribourg on October 19-21 brough together 10 researchers from different countries to present and discuss their research results on circular construction practices. We thank Samuel Holden, Barbara Lambec, Nicholas Lynch, Julie Marin, Deepika Mathur, Cristina Moretti, Ankita Singhvi and Francesco Vettori for contributing to rich discussions by presenting their research on the subject.