The built environment, consuming almost half of the world's resources extracted every year and responsible for a massive environmental footprint, is a fundamental sector in the circular transition.The circular economy has great potential to help meet global sustainability targets and the Paris Agreement's goals in particular.
Moving towards a circular built environment involves a shift in roles and business models for stakeholders active in this sector. However, barriers related to culture, regulations, market, technology and education are slowing down the transition.

The private and public sector need to create a level playing field in order for circular materials, products and services to become the new normal in the built environment. This requires bold leadership from both companies and policy-makers who have to transform the market (e.g. by introducing new valuation methods) and implement long-term policies that encourage the scaling of circular solutions (e.g. through circular procurement). Standardization, new forms of collaboration and co-creation processes are essential elements in the transition. Digital innovation, education and information sharing can further drive the change in mindset and culture that is needed to turn the circular built environment into reality.

Europe has an ambitious vision of a carbon-neutral future, a vision that integrates energy-intensive industries as well as the construction sector and its entire value chain.

Cement, which binds concrete together, is at the heart of solutions to turn this vision into reality. These solutions span over the entire cement and concrete value chain: from raw materials to production, use, re-use, and recycling.

CEMBUREAU, the European Cement Association, as part of its effort to move towards a carbon-neutral construction sector, has taken stock of progress done since the publication of its 2050 Low Carbon Roadmap in 2013 and mapped routes to a resource-efficient and carbon-neutral built environment.

The transition to a Circular Economy requires innovative business models that stimulate optimised use of repairable products, reusable components and recycling of materials. A Community of Practice (CoP) has been established in which experts from different fields have collaborated to improve the financeability of circular construction. CoP members have engaged in a case of social housing corporation Eigen Haard. This report retraces the 'learning-by-doing' trajectory of this Community of Practice. It provides tools to unlock the potential of circular construction business models.

Five main lessons have been drawn from this exercise:

1. Circular construction depends on the development of a market for used elements, products and materials.
2. Unlocking the potential of circular construction requires new valuation methods, distinguishing between land and buildings.
3. Circular construction can successfully be financed when risks and future potential are balanced. This can be supported by detailed financial modelling and leveraging key strengths of circular buildings as securities.
4. Social housing corporations are ideally suited to implement circular economy business models since both favour long-term inclusive value above mere financial profits. 
5. Collaboration and transparency support the creation of synergies between different fields of expertise (business, technical, legal, financial) to tackle the challenges of circular construction business models.

When 68 Dutch architectural firms signed a manifesto for circular construction in 2018, it became apparent that this field is committed and eager to apply circular economy principles in designing and building for sustainable development. Nonetheless there are few available resources on commencing such a process, which is why the BNA (Dutch Association of Architects) commissioned a study on 'Designing Circularity Jointly: Circular Architecture and Construction' in 2018.

The transition to a circular economy is a quest where nobody has the correct and precise information on what inputs are required to reduce carbon emissions, ensure raw materials are processed in a circular loop and the built environment is repurposed at end of life. Designing truly circular buildings requires frameworks and insights. These are summarised in the report's eight key messages:

• circular economy is a shared quest full of complexity, obstacles and uncertainty, which is why openness, trust and courage are crucial;
• architects need more circular assignments to be able to benchmark and share experiences with each other;
• architects should play a greater role in designing buildings that can actually be built, maintained and recycled;
• collaboration across the entire value chain is necessary to map out resource flows and design in a truly circular fashion;
• regulation stimulates either renovation or newbuilds, becoming an obstacle when architects attempt to fuse old structures with new materials, linear raw materials with circular processes, and outdated standards with pioneering ones;
• despite a lot of information being available, architects find it difficult to access sustainable materials that have passed the necessary quality checks;
• the lack of clear guidelines about what is circular in the construction sector limits the adoption of corresponding principles;
• there are no easily accessible and understandable tools to guide practitioners in designing a circular structure.