A Sustainable Built Environment is a key target for the European Union. This goal is reflected in many European policies such as the Renovation Wave, aiming at the improvement of energy efficiency, doubling annual energy renovation rates until 2030, as well as in initiatives like the New European Bauhaus, intending a design movement based on sustainability, quality of experience, and inclusion. Moreover, instruments such as Level(s), the European framework for sustainable buildings, are promoting the implementation of a life-cycle approach in the built environment design and transformation, by allowing the assessment and comparison of the sustainability performance of buildings along the full life cycle, based on LCA-related indicators. Circularity is seen as crucial to improve the level of resource efficiency in the construction sector in the EU Green Deal and in the Circular Economy Action Plan, where the European Commission committed to launch a comprehensive Strategy for a Sustainable Built Environment. In this framework, although the environmental impact of infrastructures is significant, little attention has been given to green infrastructure in EU circular policies although the European Commission had adopted an EU-wide strategy for a green infrastructure across Europe and a Trans-European Network for Green Infrastructure in Europe, a so-called TEN-G, in 2013. However, there is evidence of a radical change in this sense: the InvestEU Fund gives priority to investments in sustainable infrastructure, defined as one out of four EU policy windows and providing financing for projects concerning sustainable energy, digital connectivity, transport, the circular economy, water, waste, and other environment infrastructures over the period of 2021-2027. Aim of the present document is to focus on the theme of circular economy in the construction sector, by illustrating the main market dynamics relative to materials for buildings and infrastructures, and active and/or potential value chain collaborations in a circular and industrial symbiosis perspective. With the contribution of essential European stakeholders, it offers an overview of the relevance of construction and infrastructure value chains within EU economy, of their potential for circularity, resource efficiency and decarbonisation and of main barriers and levers. In fact, the present Output Paper reports the outcomes of the activities of stakeholders engagement and consultation on the abovementioned topics, developed by ENEA: • with the collaboration of Environmental European Bureau, within the “European Circular Economy Stakeholder Platform” (ECESP) in the Leadership Group Construction (2020), led by ENEA, and • with the collaboration of alchemia-nova and Innowo, within the ECESP in the Leadership Group Construction & Infrastructure (2021), led by Holland Circular Hotspot. The Paper contains different contributions from the stakeholders involved in this two-year consultation, within a more theorical framework defined by ENEA with the contribution of alchemia nova, Innowo and European Environmental Bureau, and the identification of the next steps to boost circularity in the construction sector.