Circular, from design to demolition

"Colruyt Group is one large construction house", says Mathias Steels, responsible for the in-house design office. "Every year, we have some fifty larger construction projects of one million euros and more on our capacity planning." However, the construction sector is moving. Everything has to be more efficient, more sustainable. "We examine new materials and procedures and also experiment with organic waste flows, urban mining and re-using materials to close the cycle", says Hilde Carens, Sustainable Construction materials Project manager. "By 2050, we will evolvetowards a circular patrimony."

From brandbook to design

Our own design office consists of 45 people who tackle the building shell: 15 designers, about 20 drafters and 10 'conceptualists'. With its product developers, architects and interior architects, the Retail Design department feeds and translates the 'brand book' into a style guide, the 'look & feel' of the various store formats. "This is when we will apply new materials, for example", explains Steels, referring to Bio-Planet that accentuates the store format's character by means of its choice in furniture and walls. "All of this is laid down in criteria or standard lists." In the interest of economies of scale, of course. On a site near the group's headquarters, he has a few hundreds of square metres at his disposal for the life-size prototyping of concepts and live testing. "If the new criteria are finalised and we find a suitable plot, it's the designers' turn to guide the design through the various decision stages or 'gates' 'according to the master plan'. When all the design elements are clear, the drafter sets to work to draw the details in 2D and 3D software. This depends on the permit file. "It's all about increasing the chances of success as much as possible. Whereas specialists are sometimes working on smaller fragments, it's the team work where everyone excels in their strength."

Circular materials

During the entire building project, Hilde Carens, Sustainable Construction materials Project manager, is also on duty. "My task is to realise a construction that is as sustainable as possible." How does she do this? "We screen older buildings. Which materials do they contain and how were they used? This teaches us how we can do things differently in the future. How can we use materials in the building in view of reuse, high-quality recyclingand residual value? We also look at materials from urban mining, that already contain a fraction of 'post consumer recycled content"." We also choose elements that can be adjusted during the buildings' life span. Think of flexible interior walls and dry construction facing bricks. Of course, maintenance and repairs of the building are on the agenda. Finally, towards the end of the life span, she looks at the possibilities to reuse materials internally and externally. "We examine a lot of routes to realise a closed cycle and thus improve the environmental impact step by step."

Collaborating on circularity

In addition to the internal research, we have partnerships with universities and the business community. "We act as external tutor for master theses. This allows us to come into contact with suitable profiles very early on, and at the same time trigger research directions at universities." Collaborations with Vlaio and OVAM for example, and initiatives such as Flanders Circular are also more of a rule than an exception. "For example, we are examining with the supplier and processor how we can make a post-consumer recycled product from aerated concrete." And what if concrete foundations would not be poured, but laid in prefab elements?

Recently, the students from the 'Circular Construction' training at UGentuniversity visited our head office in Halle. We collaborated on that training, more specifically on the part about circular construction in practice. Hilde Carens explained how we see circular construction and how we apply the ICEBERG project in our organisation for example. A guided tour through our test centre immediately made this explanation very tangible. Not only are we testing new concepts for our stores there, but we also examine circular construction solutions.

Urban mining of concrete...

Colruyt Group is also active in international research projects. In the EU ICEBERG project, it examines, along with 35 partners from 10 different countries, innovative and cost-efficient solutions to harvest construction materials and convert them into new products, ready for reuse.* "Urban mining. What materials does our patrimony contain and how do we get them out at the end of their life span?" How to demolish selectively and sort on site? What can be used of high quality and what not? "The focus in ICEBERG for Belgium is on concrete. Together with Vito and Orbix, we are examining the production and impact of carbonation blocks made from our own concrete."

"We also look at our own organic residual streams that are not yet used with high quality", says Carens, who highlights the low impact of these materials. In doing so, Colruyt Group works with Kamp C and Biobased Creations for the 'The Exploded View Beyond Building– The Exploded View' project, an exhibition in the form of a completely equipped building in which supply companies can demonstrate their innovations in organic materials. In 2023, this Dutch exhibition is coming to Kamp C, the Provincial Centre for Sustainable Construction & Living in Westerlo. "What materials meet our technical specifications and which residual streams from our own companies can we use for this in order to avoid other primary raw materials?"

... and bricks

At the end of November, a new Colruyt store was opened in Zoersel. A system of dry-stacked facing bricks was used for the façade. These profiled hand-moulded bricks are clicked into place with stainless steel clips and wall ties. No more glue or mortar is needed. We first tried out the system on our test site. The steel consumption is slightly higher but no more mortar is used, as a result of which the installation no longer depends on the weather and is faster. During use, the façades can easily be adjusted and the naked brick can easily - and especially cleanly - be recovered afterwards, when the building changes function or is at the end of its life span. "The value of a pure ceramic stone is fairly fixed. After complete evaluation, in which we look at the environmental impact and the total cost of ownership (TCO), this can be applied to the rest of our patrimony." Meanwhile, Carens is drawing the 'material passport' for all used products and negotiates with supply companies about the take-back of recovered materials at the end of the life span. "Our stores have a life expectancy of 35 to 40 years. Our suppliers now have to start thinking about this possible take-back."

*The EU ICEBERG project received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 869336 . (

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