Through the Big Buyers Initiative, a working group on Circular Construction Materials brought together public procurers representing Amsterdam, Belgian Post, Brussels city.dev, Budapest, Haarlem, Helsinki, Lisbon, Oslo, Paris, Porto, Rotterdam, Stavanger,Vantaa, Vienna and Zurich to promote circular economy approaches to the construction sector, focusing on construction materials in civil and building works, and covering the value chain from disassembly to material transformation and new construction. This report captures their learnings.