The importance of a circular economy should not be underestimated when making the transition to a low-carbon society. More than half of our CO2 emissions come (directly or indirectly) from the materials we use. The production of building materials is particularly notorious for the major impact it has on the climate. Earlier this year, VITO signed the Green Deal on Circular Construction, a commitment to support the transition to a world of circular construction in Flanders.

Circular construction means much more than simply reusing and recycling building materials. By focussing on change-oriented construction, architects and product developers can allow the buildings and their components to evolve along with usage requirements. And new business models can encourage contractors and product and service providers to fulfil the planned life cycle of a building project differently: performance-oriented, adaptable in accordance with the needs and/or the recovery of valuable materials.

Together with the Public Waste Agency of Flanders (OVAM), including the Flanders Circular team, VITO is strongly committed to encouraging circular construction in Flanders. Both organisations are involving as many partners as possible from the extensive construction sector: from small and large construction companies to consultants and facilitating organisations to research and even educational institutions. "We have noticed that there is a great deal of interest in circular construction", explains Brigitte Mouligneau, Circular Economy Transition Manager at OVAM. "Of the more than 130  current projects in the field of circular economy, over 40 are construction related. That speaks for itself."

Experimental and learning environment

The Green Deal on Circular Construction is a new initiative of the Flemish Ministry of Environment, Nature and Agriculture, OVAM and the Flemish Construction Confederation. "The plastics federation essenscia is also involved via the latter (as a member of the public-private Flanders Circular partnership). This is important because construction waste also contains a considerable amount of plastics", explains Mouligneau.

Based on the Green Deal, OVAM and VITO have initiated a partnership around an experimental and learning environment, in which experiences are exchanged. "The aim is for partners to implement concrete innovative circular projects", explains Mouligneau. "This can range from the use of new sustainable materials to eco-design and change-oriented construction. We work with an open mind here: everything that can further help us close the construction loop is taken into consideration."

The end of February 2019 marked the official starting point for this. Since then, more than 290 participants have signed up. By doing so, they enter into a commitment to realise at least one project that they can choose and devise themselves. Participants will then be able to exchange their experiences with one another during so-called inspiration sessions. Mouligneau explains: "We are hoping to organise these sessions four times a year. What is more, we are developing an online platform to share knowledge and experiences even more easily."

Beyond the low hanging fruit

In addition to this initiative, OVAM and VITO/EnergyVille, in collaboration with the Scientific Technical Centre for the Construction Industry (WTCB), the University of Hasselt and the Vrije Universiteit Brussel, have launched an additional (research) project, in the form of a living lab. This looks beyond the low hanging fruit – call it circular construction for advanced users. "This project deals with obstacles in circular construction, such as regulations, legal matters relating to contracts or labour taxation", explains Wim Debacker of VITO/EnergyVille. "Our researchers provide their expertise in this living lab."

The living lab consists of two subtasks: during the first eighteen months, the focus will be on urban mining, whilst over the next 24 months, the emphasis will be on change-oriented building. Debacker explains: "With urban mining, we are hoping to create a solution for the legacy of the existing building heritage. We can reduce the large amount of construction and demolition waste by consciously finding useful applications for this waste."

Building As Material Banks

In the meantime, the European Building As Material Banks (BAMB) project came to an end at the end of February 2019, when the Green Deal on Circular Construction was launched. This project studied bottlenecks – 'systemic barriers' – that stand in the way of the development of a circular construction model. Within the project, which involved fifteen other European organisations in addition to VITO/EnergyVille, the focus was on three system changes. "First of all, the focus was on a different way of designing buildings, materials and products", explains Debacker. "Today, buildings are primarily designed for one set function. This is problematic, as needs change faster than buildings. In the BAMB project, we studied how we can already integrate several functions into the building plans during the design phase and ensure that buildings can be purposefully and easily dismantled. After all, when the function of a building changes, we do not only want to recover materials, but also, and more importantly, entire components."

The second system change involves the entire value network of a building, from contractors, architects and builders to building managers and demolishers (or 'dismantlers'). Debacker explains: "Now we are seeing that although small clusters of architects, contractors and consultancy agencies are working together more, little account is taken of other players who are active in the later stages of the building's life cycle. A circular model requires cooperation throughout the entire chain, for example by sharing data and information regarding products, components and buildings. The development of material passports plays an important role here. This digital tool can be used to bring all information about a specific product in a specific building together and share it. The passport not only contains traditional parameters such as density or technical performance, but also information regarding assembly or disassembly. This instrument can help builders and contractors to carry out construction work in a reversible and change-oriented manner."

Thirdly, there is still the challenge of creating different value for buildings than is the case today. "It is no longer a matter of simply carrying out building work as cheaply as possible. "We need to evolve towards business models that take into account the costs and benefits over the entire life cycle – and these models must also be social and environmental", explains Debacker.

The BAMB project was action-driven, just like much of VITO's research. Work was thus carried out on a number of pilot projects, such as the design of a transformable building based on a steel skeleton or a renovation strategy for prefabricated student accommodation.