© Florian Spring
Shaping transformation
Even small steps can have a big impact: When, just a few years ago, LXSY Architektur implemented circularity principles in the interior design of the Impact Hub Berlin at CRCLR House in Berlin-Neukölln, they were almost smiled at, recalls co-founder Margit Sichrovsky on a summer evening in 2025 in Munich. Setting up material storage facilities, using reused components, or developing prototypes from existing components – all of this had rarely been tried on a large scale before. Today, however, circular construction is no longer an exception, but a necessity.
On July 23, employees, colleagues, and friends gathered at Dietrich Untertrifaller's Munich office for an evening of lectures and discussions on the facets, hurdles, pioneering projects, and visions of the current construction practice. For the speakers and audience have one thing in common: They are not only dedicated to classical architecture in their everyday work, but also want to promote sustainable transformation.
Circular construction from three perspectives
“We need to renegotiate the way we design our living spaces”, says Munich office manager Fredi Botz in his introduction. “How can we create buildings that give more in return than they take, how can we build for the future, and how can we incorporate circularity into our work?” asks Bregenz architect Cemile Stadelmann, who initiated the evening together with her colleague Laura Untertrifaller.
Answers to these questions come from at least three outside perspectives. Whether in the everyday office life of LXSY in Berlin, at the manufacturer and industry representative Lindner, or the Supertecture collective, which, with its geographically and culturally widely spread experience, seeks to translate reduced concepts and social responsibility into the local, overly complex construction practice.
© Jacqueline Horn
© Jacqueline Horn
Berlin perspectives
One of the firms that early and comprehensively committed itself to the circular concept is LXSY Architektur in Berlin. Founding architects Kim Le Roux and Margit Sichrovsky were joined by Wiebke Ahues as a partner in 2024. Together with a team of around 15 other employees, they consistently follow principles that are otherwise rare in the architectural landscape. For LXSY, form not only follows function, but also the availability of existing resources. The reuse of building components, the adaptation of planning and processes to existing situations, the reuse not only of given materials but also of waste and residues, consideration of the different life cycles of building layers, and the urgent questioning of established standards in construction: all of these are premises of LXSY's design practice.
Recycling is not the solution, but rather the “very last possibility” at the end of a chain of previous measures, preceded by demand reduction, repair, or reuse, explains Margit Sichrovsky in her keynote speech in Munich. She advocates a permanent urge of viewing buildings as future material suppliers. New buildings should always be able to be dismantled and sorted by material type. The Impact Hub Berlin, completed in 2022 – a co-working concept in the CRCLR House on the site of the former Kindl brewery in Neukölln – clearly demonstrates that the circular method can work. It features old wooden beams in hemp-lime walls built in-situ, numerous carpentry scraps, and many other elements that have already been used before or can be reused elsewhere due to reversible screw connections.
Planning for future reuse
This approach has also been practiced in Dietrich Untertrifaller's office for many years. Examples include a wooden structure that was dismantled and reused in 2015 during the renovation and expansion of the European centre Hochreute, a modular construction system for the Hamburg Finance Academy, the plans for a technology campus in Straubing, and the future KREA residential project in Munich's creative quarter.
The fact that many circular economy projects are still based solely on the courage and commitment of individual protagonists can also be seen as an appeal to politicians. A mandatory building material passport for new public buildings is currently being held back at the federal level. Besides, many hurdles such as component sourcing, logistics, warranties, and approvals affect only a few instead of many. “It cannot be that an architect or a builder alone has to bear the entire risk.” It must be shouldered “by the team and by society as a whole. This is the only way that we can transform our construction industry into a circular economy,” Sichrovsky concludes her presentation.
Alternative business models and the necessary contribution of the industry
The construction industry has to play a key role in this transformation process. One of its representatives that understood this early on is Lindner Group, a manufacturer and supplier of complete solutions for interior design, building envelopes, and building technology based in Arnstorf, Bavaria. They are pursuing the circular approach with its own unique business models. Depending on their life-cycle, products can be rented or used in a “purchase with return” model. In this case, the elements are dismantled by the manufacturer and returned to the cycle.
Sustainability specialist Marcel Gröpler, who traveled to Munich for the event and immediately relativized the specialist title by pointing out that he still has a lot to learn, says: “If a building is not circular, it does not deserve the title of being sustainable.” The company employs 2,000 of its own fitters, who are also dismantlers, he says. This enables the professional dismantling of its own products, their return transport, and their processing into a new product. Whether it's a raised floor, partition walls, ceiling elements, or entire room-in-room systems, a possible new use must be considered from the outset, according to Gröpler.
© Jacqueline Horn
The value of materials that already have been used
After an initially modest eco-balance, a significant reduction in CO2 emissions has now been achieved within the company. The major drivers were materials and energy. Production and processing now largely take place using self-generated renewables or in closed water cycles, for example. Circular value creation from the company's own products also makes a decisive contribution, but this only works if it is economically viable. Gröpler uses a number of project examples to illustrate the extent to which forward thinking contributes to economic efficiency. And he explains, why the company will soon even be able to process external plasterboard waste.
Another project by Dietrich Untertrifaller is an example of reuse: the replacement construction of the Hinteralmhaus in Upper Styria will use components from the demolition of the old hut. In addition, a mineral flooring from Ardex, which previously served at this year's BAU trade fair at the stand of the Vienna-based material service agency Ofroom has been cut into panels and will be used as a secondary material for some rooms in the new hut.
From the wide world back to the Allgäu
Till Lill, the third speaker of the evening, is co-founder of the non-profit architecture collective Supertecture. For over a decade, the group has been pursuing social construction projects “with minimal resources and maximum impact” in the Global South. The planners are now transferring their experience to southern Germany, more precisely to the Allgäu region, where the group is literally expanding its new headquarters and from where it still operates around the world.
In Munich, Lill vividly demonstrates how, for example, 700 “earthquake windows” were used to build a school extension in Nepal, or how an entire house was built from 15,000 bricks collected by the local population. He also shows, how straw, pine needles, and cow dung can be used in construction, and how Supertecture experimented with rice husk ash as a substitute for cement in Africa. Lill demonstrated the audience, what melted plastic or shingles from window frames look like as new roofs for a kindergarten. He also explains, why, out of sheer necessity, “every flip-flop can serve as a sealant for corrugated iron,” and why many construction projects “were not only created from reused materials, but from the solidarity of the people.” All of these suddenly no longer are droll anecdotes, but extremely instructive input.
© Jacqueline Horn
Pragmatism, which is learned in crisis, disaster, and war zones, can be complemented by vision, sustainability, participation, and spatial qualities, in order to become an authentic architectural project with a unique aesthetic. It is not only the creators of Supertecture who are visionary, but increasingly also builders from their home country, through whom the collective can now gather references also in Germany. With volunteer work, crowdfunding, and a rich network for exchange and engagement, Till Lill is convinced, that we will be hearing a lot more from Kaufbeuren – the “world capital of circular construction” – in the future.
© Jacqueline Horn
Collective effort for a positive impact
As always, the evening culminates in a lively discussion. When asked how much convenience the architectural practice can still afford, Patrick Stremler sets an ambitious goal for his firm: “We want to build houses that have a net positive impact on nature only.” This requires individuals and groups alike to take responsibility. “We live this as an office despite the field of tension we work in – for example, not being both client and product developer at the same time. So we have to constantly renegotiate the goal and bring our idealism to bear. But it's a feasible task,” he concludes.
Rethink as an enriching format
Rethink is the name of the new event series that began in March at the Bregenz office with a contribution to the demolition debate and the HouseEurope! initiative. The thematic bridge extends to Munich at the end of July. “The largest reusable component is the existing building,” Margit Sichrovsky summarizes at the end of the discussion.
With the usual livestream to all locations in Europe and invited guests in Munich's Glockenbach district, important impetus for the own work was once again gained – and perhaps also sent out to some extent. The next edition of Rethink at the end of the year in Vienna will focus on inclusion. This is a task that always affects urban society as well as planners and decision-makers. The Viennese perspective surely promises to be enriching, once again.
© Jacqueline Horn
Text: Sabina Strambu, August 2025
