From shredded jeans to recycled railings to revived factory floors: the circular economy saves energy, resources and emissions, while creating unique atmospheres. So why is it still not the standard?
Kvadrat Really, a spin-off of Danish textiles group Kvadrat, shreds old jeans, t-shirts and bedding, and compacts them to create resource-efficient desk tops. Situated on the outskirts of Barcelona, Honext has partnered up with local waste treatment plants, turning processed waste paper foam into high-density boards that can be used as an alternative to plasterboard. While Austrian start-up, Hempstatic, takes hemp fibres, a waste product from food production, and turns them into biodegradable acoustic panels for buildings and offices.
“The production of hemp seeds and hemp oil creates a lot of waste,” says Elena Yaneva. A qualified civil engineer, Elena and her partner, Igor Fekete, launched their start-up in Vienna three years ago. “It’s a win-win situation for everyone involved because the farmers don’t have to worry about disposal, while we get a valuable raw material for our product.” After chaffing, the hemp fibres are mixed with lime, water and natural adhesives to create square and hexagonal Hempstatic panels. Thanks to their porous surface and high specific weight (up to 300 kg per cubic metre), they make the perfect sound absorbers.
But it’s not just about recycling – reuse and urban mining are also turning the office space on its head. At Place Masui in north Brussels, a former printworks is being converted into office space and workshops for social and artistic organisation Zinneke.
Working closely with Bouwmeester Maître d’Architecture – a sort of town architect which runs tenders on behalf of contractors, emphasising innovation, quality standards and inclusion of the next generation – they have managed to retain the original structure of the building and use it as a sort of raw materials warehouse for the upcoming renovation.
Whether it’s windows, door leafs, door frames, floorboards, steel brackets, wooden slats or entire staircases, every single component has been carefully removed, cleaned, repaired, adapted and, finally, reinstalled somewhere else, in a new configuration. Thanks to this, the project team has managed to preserve 94 per cent of the historic building. Other materials, such as radiators, steel beams, railings, mineral insulation wool and even 300 square metres of oak flooring were brought from nearby building sites, giving the new Zinneke workshop a sort of punchy flair. “We do a lot of work on urban entropy,” says Renaud Haerlingen, co-founder of inter-disciplinary planning collective Rotor, which began specialising in reuse and recycling several years ago, “on the inequality between old and new, big and small, system and singularity, interchangeable and unique.” He continues, “Old, pre-used materials have a shimmer, they have identity, they are bursting with history. That quality is almost impossible to achieve in a new build. This is also a conscious commitment to resource-efficient construction which reduces emissions. That is the future.”
Similar ventures can be found in other countries too. They include Concular (Stuttgart), Bellastock (Paris), baubüro in situ (Basel), international platforms like Harvest Map and Bauteilnetz, and the two Austrian initiatives, BauKarussel and Materialnomaden. While from a legal perspective the use of second-hand building materials and products remains complex – because, legally speaking, a material automatically becomes bulk or construction waste the second it is removed – there’s no stopping the dedication of all those who subscribe to the circular economy.
“Previously, the way to demolish old buildings was to crush everything and take it away in order to comb through the pile of rubble at the tip and pick out the few remaining valuable materials,” says Thomas Romm, architect and founder of the BauKarussell project consortium, founded in 2017. “It’s hard, dirty work, anything but sensible and efficient. Instead, what we’ve done is focus on removing the valuable materials from the building on-site. Not only does that limit waste and disposal costs, it also reduces the number of trips, the amount of diesel consumed and, ultimately, carbon emissions.”
“We can’t go on like this. We have to get politicians, businesses and the construction industry to revise their thinking, to make reuse and recycling the rule, not the exception.” With that in mind, b+ recently partnered with ETH Zurich and a whole host of institutions, architects and political testimonials to launch the European Citizens’ Initiative “HouseEurope!” which recently won the OBEL Award. The initiative aims to collect one million signatures by January 2026, as a way of forcing the topic of “Renovation instead of demolition” onto the political agenda – with the aim of getting the EU Parliament to draw up a regulatory framework for the circular economy.
BauKarussell’s most well-known urban mining projects include the old Coca Cola factory on Triester Straße in Favoriten, the Ferry Dusika Stadium in Leopoldstadt, the server centre on Rathausstraße, Vienna, the former Reininghaus Brewery in Graz, and a whole host of schools and hospitals. Depending on their condition, these buildings offer a fair amount of material value. Highly prized building materials such as aluminium, copper wiring, doors, door frames, fittings, parquet flooring, banisters, railings or historic cement tiles are sorted, separated, cleaned and repaired before being set aside – and in the ideal scenario re-sold.
One such passionate purchaser of these materials is Olaf Grawert, architect and partner at Berlin firm b+. Among his favourite reuse objects for offices, apartments and all sorts of cultural buildings is Luigi Colani’s legendary ceramic basin, manufactured by Villeroy & Boch between 1970 and 1979. “It’s one of the most famous pieces of 20th-century bathroom ceramics. Thousands were produced, but for some reason no-one wants them anymore because most people think they’re ugly,” explains Grawert. “Not us. This unloved, unwanted, oft under-appreciated piece is exactly the aesthetic we want to retain – not just with a view to a circular economy, but in terms of culture and architectural history, too.”
This is also what prompted Grawert and his firm, b+, to leave central Berlin three years ago for an old industrial building. In 1987 – just two years before the fall of the Berlin Wall – VEB Elektrokohle built a factory in the industrial district of Lichtenberg, in East Berlin. The steel structure of the blast furnace hall has long since been torn down and recycled, but the two stair and silo towers remain, concrete witnesses of a lost time. One of those towers – standing 42 metres high and with 199 steps top to bottom – is now home to the b+ studio, offering spectacular views of the zoo, museum island and the TV Tower in Alexanderplatz.
Wojciech Czaja