Together with the University of Antwerp, we submitted the project to Flanders Circular in 2018 after the Open Call that would provide financial support for all kinds of projects in the context of circular building.

With the project, Flanders Circular wanted to try to demonstrate that school building projects can be tendered with a focus on reuse and disassembly.

A thorough historical analysis of the existing buildings and an in-depth analysis and inventory of the materials present were the basis of the renovation design and formed the focus in the technical specifications, alongside circular properties for new materials. Maximising the preservation of the valuable parts of the historical campus buildings and reversible construction was, after all, the objective.

RETAINED AND REVERSIBLE CONSTRUCTION

The non-load-bearing internal walls of the office buildings on the site were the subject of the research around the application of new circular building materials.

A survey of the Belgian market was carried out, which showed that there was too limited a number of bidders for a sufficiently objective competition. Therefore, a so-called performance tender was eventually used, with the contract being awarded on the basis of an LCA score of the materials proposed by the various bidders. The architects inventoried all circular materials and products used and processed them in an online overview on ProReMat.be. The interior walls that were finally applied are movable system walls, thus contributing to the reversibility of the project.

A parallel project then focused on the recovery of existing materials. Materials that could not be reused on site, the design team tried to give a second life in other building projects through external parties. Some interior doors found their way to a private home and the ballustrades, flat gas and some other loose material were recovered for the students of the interior architecture course at the University of Antwerp, who used them to make a circular piece of furniture.

The circular card was also drawn in terms of techniques: the existing main power supply cables were reused, as were the main electrical boards and the fire alarm control panel. All techniques were installed in surface-mounted form and can therefore be easily dismantled. Sustainable materials and a sustainable process were chosen that minimised energy demand.

LESSONS LEARNED

Our sustainability consultant Katrien Van Lierop summarises the main lessons learned from the field experiment as follows:

it is important that the audit and materials analysis of an existing building is done before the terms of reference or at least before the start of the design phase. This will encourage the reuse of the building and/or its materials much more;
the principles of circular construction should be supported by all players participating in the construction project. Clear and convincing communication of those circular principles will help determine the success rate of their integration;
three or more independent circular products are not always available in order to be able to tender a circular proposal in public procurement. A performance specification sometimes offers a solution. Finding buyers of recovered building materials is not always easy either;
Requesting bids with an imposed upper limit on cost price and assessing them on the basis of an LCA or LCC is possible. It is stimulating if the client actively asks the market itself.

ir. arch. Katrien Van Lierop

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