Circular construction: more and more construction companies are realising that this is where the future lies. But for a thorough make-over of their current operations, there is often still too much uncertainty. Reynaers Aluminium, a developer of window, door and curtain wall systems, was no exception. Together with VITO, the Duffel-based company is currently looking for circular building solutions. At the end of the journey, these solutions will be compiled in a design guide for architects.

In a 2-year project (ending late 2021) and supported by Vlaanderen Circulair, Reynaers Aluminium, together with VITO and experts from the VUB, is looking for opportunities for aluminium exterior joinery within circular construction - hence the name of the project: Windows of Circular Opportunity. Their insight into these business opportunities should remove the persistent uncertainty surrounding circular construction in the construction sector. 'We are still currently working out exactly where we are going with "circular" in our industry," explains Kurt Van Den Bergh from Reynaers Aluminium. 'What does the market expect from us, and how can we meet expectations? Up until now, we have primarily focused on the performance and sustainability of our products, their applications and the production processes: for example, by optimising them in terms of energy and the environment'. 

As part of the project, VITO already carried out a so-called circularity scan on Reynaers Aluminium's extensive and varied product range last year. But of course the circular revolution is broader and more extensive. 'We need circular solutions at building level', according to Carolin Spirinckx from VITO/EnergyVille. 'From that level, we can feed back insights to the level of exterior joinery companies such as Reynaers Aluminium. That way, new opportunities may arise that we are currently unaware of, possibly in the form of differently defined products and services'. In this context, in December Reynaers Aluminium and VITO brought together stakeholders from the entire value chain in the first of three workshops organised in accordance with the co-creation formula. 

Tailored guidance

One person who does work primarily at the building level is the architect. One of the objectives of the project is to compile a design guide for architects with circular solutions for exterior joinery. 'Via a sounding board group with architects, circular experts and the industry, we want to improve the circularity of the current solutions,' says Spirinckx. 'And through the co-creative workshops, we adapt the needs of architects and opportunities in the chain into suitable technical solutions. This should then all result in a complete guideline tailored to the architect'. 

Today there are already general guidelines on circular construction, but they are not specific enough and not focused on external joinery. 'First and foremost, it's a matter of adapting the existing general guidelines into facade systems,' explains Damien Trigaux from VITO/EnergyVille. This general framework was partly developed by VITO, under the impetus of OVAM. 'We have therefore been looking into circular construction for a long time. In this regard, not only do we work qualitatively, but also quantitatively from the perspective of the entire value chain, by implementing a life cycle analysis (LCA). This allows us to examine the difference between the business-as-usual scenario and the more circular solution'. In the collaboration with Reynaers Aluminium, VITO will therefore subject a number of specific cases to an LCA. Finally, we also look at it from a financial perspective,' explains Spirinckx. 'What environmental benefits do we achieve, what is the investment cost and can it be justified at the end of the ride?' 

After all, it all needs to be financially viable for investors. 'The cost of circular construction currently puts building principals off', admits Stefan Vandervelden from Reynaers Aluminium. 'Also because the benefits of circularity are often not immediately visible or tangible, and moreover, they are more long-term in nature. As a result, there is uncertainty about the return on investment. As a result, not only building principals but also financial institutions are holding back'. 

Crucial role for governments

According to Spirinckx, it remains to be seen whether the cost is higher. 'We still need to specifically look into this, and it is crucial that we are transparent in this regard. As such, this is also discussed in depth during the workshops. We compare business-as-usual with circular, and zoom in on both the cost and the environmental aspect, for the entire value chain. We then look at the shifts that occur as a result of circular building solutions'. 

As is the case in many areas, the government can also play a crucial role in the transition to a circular construction sector. This is already happening to a certain extent with our neighbours to the north. The Dutch government already incorporates criteria such as the Environmental Performance of Buildings (MPG), the environmental cost indicator (MKI) and the detachability index in its public tenders,' reveals Vandervelden. 'That way, it plays a guiding, however still limited, role towards more circularity'. In Belgium, too, invitations to tender already mention circular criteria, as part of so-called green public contracts. 'Unfortunately, very few quantitative requirements are imposed, meaning that the contractors can interpret them as they see fit. That is too non-binding. Tools such as TOTEM (to optimise the environmental impact of buildings and building elements) and GRO (the sustainability meter, of the Facility Company which focuses intensively on circular construction) can help in this regard'. 

But first and foremost, the construction team needs to be better informed. 'In many buildings today, the circular construction principle is still limited to a few materials', adds Van Den Bergh. 'There is currently too little knowledge and experience in the field to apply it across the board. We hope that our draft guide will soon change that'. 

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