The EU Waste Framework Directive 2008/98/EC states that all member states should take all necessary measures in order to achieve at least 70% re-use, recycling or other recovery of non-hazardous Construction and Demolition Waste (CDW) by 2020. In response, the Horizon 2020 RE4 project consortium (REuse and REcycling of CDW materials and structures in energy efficient pREfabricated elements for building REfurbishment and construction) consisting of 12 research and industrial partners across Europe, plus a research partner from Taiwan, was set up. For its success, the approach of the Project was manifold, developing sorting technologies to first improve the quality of CDW-derived aggregate. Simultaneously, CDW streams were assessed for quality and novel applications developed for aggregate, timber and plastic waste in a variety of products including structural and non-structural elements. With all products considered, innovative building concepts have been designed in a bid to improve future reuse and recycling of the products by promoting prefabricated construction methods and modular design to ease future recycling and increase value of the construction industry. The developed technologies and products have been put to the test in different test sites in building a two-storey house containing at least 65% of CDW. © 2019, © 2019 The Author(s)..