From linear to circular with Concular

“We want to radically change the industry,” says Annabelle von Reutern, Head of Business Development at Concular. That and nothing less is the start-up’s goal. The company tackles challenges in the construction and real estate industry; Concular wants to help reduce both waste and CO2 emissions with one idea: to promote circular construction. Instead of linear, all players in the industry should think, plan and operate in cycles. Concular offers a platform for such cycles. Used materials from buildings that are demolished or converted end up in other construction projects instead of being thrown away. Even before demolition or conversion, the Concular team checks on site which materials and components are suitable for reuse. They take measurements and photos. They enter all the details into a digital database. If the people involved in the demolition of the building do not use the recovered materials themselves for a new project, interested parties can buy the materials from Concular’s online store. These can be doors or lights, bricks or entire kitchenettes. What is sold within a certain period of time – demolition or conversion has to start at some point – is dismantled by dismantling companies. If possible, reclaimed materials are transported directly from one construction site to the next. This saves on transportation and storage costs.

Digitize and distribute, reinstall and also rebuild: Concular wants to participate in all of these processes with its holistic approach. The start-up wants to be the ecosystem for circular construction. However, Annabelle von Reutern is not satisfied with just digitally recording the existing building stock, because it is urgent: “We need to bring materials back into the cycle today and not in 30 years’ time.” After all, the construction industry is responsible for a large proportion of the waste generated. “And we have no time to lose,” she says. According to the Federal Environment Agency, more than half of all waste in Germany in 2020 was construction and demolition waste. In addition to excavated soil, which accounts for the largest share at around 60 percent, this includes road rubble, building rubble, construction site waste and plaster-based construction waste. Construction and circularity have already been merged in the start-up’s own name: Concular was created from the words “construction” and “circular”. The team comprises 45 employees. Concular has already completed around 250 projects, from smaller consultations to larger projects. One of the buildings from which Concular has recovered materials was the old municipal library in Augsburg. Here, Concular, the Augsburg State Building Authority and Augsburg University of Applied Sciences joined forces; architecture students helped to collect the materials. Another example is the Mercedes-Benz Arena in Stuttgart, which is being converted for the upcoming European Championships; Concular sold grandstand seats, among other things. And currently, in May 2023, interested parties can buy turnstiles from the Frankfurt office building “Prisma”, lights from the Behrensbau in Düsseldorf or façade components from former FAZ buildings in the online store. However, it originally started with a different platform: the future founders of Concular have been gaining experience in the sale of used building materials for around ten years. Back then, Dominik Campanella, Julius Schäufele, Marc Haines and Ulrike Schock launched the online marketplace “restado”. With this, they primarily reached private customers and small businesses. “It’s nice when you save three doors from a detached house. But it’s even nicer to get 300 doors from an office building back into circulation,” says von Reutern. Campanella, Schäufele and Haines then founded Concular at the beginning of 2020. Their start-up is aimed at larger projects and all players in the construction industry. Manufacturers and architects, dismantling companies and property owners – Concular wants to bring everyone together to establish material cycles in the construction industry and make them more sustainable. Because they are convinced that everyone has to get involved. “That really is the biggest challenge for us: bringing everyone together and transforming people’s mindsets from linear to circular,” says von Reutern. Concular is also committed to establishing standards: The start-up has initiated the development of DIN SPEC 94184. This is intended to describe a standardized procedure for recording building materials prior to demolition and renovation work. The procedure then forms the basis for assessing the potential for subsequent use.

In addition to the Stuttgart location, Concular has a branch office in Berlin as well as colleagues in several German
and one Austrian city. In Berlin, the start-up is based in the “CRCLR House”, now known as the Impact Hub. “Of course, this is totally in line with our philosophy,” says von Reutern. What used to be a Kindl brewery warehouse is now a co-working space in the middle of Berlin-Neukölln. Additional space and apartments are being created on the new storeys. The existing building was renovated, converted and extended according to the plans of architects from Die Zusammenarbeiter ; the interior fit-out was carried out by LXSY Architekten. The planners paid attention to a circular construction method and reused materials were also used. Concular contributed very little here, just a few doors; the start-up was still small at the time. Now, however, it supplies the material passports for the building. These are part of the digital side of Concular’s approach. Material passports – called life cycle passports by the startup – can be used to store all the information about the materials used in a building. This creates a digital “twin”. The service is aimed at both builders and property owners. They can use the data for reports on the sustainability of a building, for example. The governing parties also want to introduce digital building resource passports – at least that’s what they wrote in their 2021 coalition agreement. The German Sustainable Building Council (DGNB) has developed and published a proposal for what such a passport could look like in consultation with various stakeholders. The idea of the building resource passport is to record information on individual buildings – on resource use, climate impact and recyclability , as the DGNB writes. This is intended to create the basis for a circular economy in the construction sector. According to the DGNB, its resource passport should be able to be linked to future federal or EU measures, and the resource passport can also be used for DGNB certifications. The DGNB passport can be created using Concular’s Life Cycle Passport. However, Annabelle von Reutern points out that a material passport in itself is not enough, because if planning is not circular and materials cannot be dismantled non-destructively, you can only end up disposing of everything. Instead, the “Circularity Performance Index” that Concular is developing is intended to help assess buildings. The index uses several factors to show how sustainable and circular a component or building is.

Is there a risk that Concular’s approach will be exploited, i.e. greenwashing? The question comes up frequently, says Annabelle von Reutern. “In my opinion, this shows the German mentality quite clearly,” she says. Those who drive change are not met with benevolence, but with skepticism. And that makes her angry. “That’s really amazing to me: that we immediately criticize the people who start at all because they might not do everything perfectly. But at least they are doing something. They move, they move forward, they try things out, they fail, they try again. And I celebrate that,” she says. That’s why Concular is open to anyone who approaches them – including large corporations that have not previously presented themselves as sustainable companies. She doesn’t want to deny that greenwashing exists. However, Concular wants to encourage its partners to become really active through the Circularity Partner Program. The aim of the program is to enable companies to network. However, only those who implement a project with Concular within a year can remain a member. “We don’t want to give people a green veneer if they don’t do anything,” says von Reutern. What happens next? Annabelle von Reutern names several ambitious goals: that Concular is the platform for circular construction, that nothing else can be built other than circular. She also wants to record the entire building stock in Germany “so that we know the urban mining potential long before a demolition or conversion takes place”. In short: Concular wants to radically change the industry. It may or may not be long before these visions are fully realized. Concular is already involved in the German Pavilion at the 18th Architecture Biennale in Venice this year. Entitled “Open for Maintenance – open due to renovation”, the German contribution uses only materials from last year’s art biennale (see also Baumeister 5/2023, from page 46). These materials are recorded using Concular software. Plywood panels of different cuts, insulating material and various pieces of furniture are photographed, their dimensions taken and their condition and origin noted. All this information can be viewed online, as a digital twin has also been created here – in this case of the depot. The inventoried materials should be able to be reused in a targeted manner. Just as Concular envisions for the entire construction industry. This will not be the last project in which they record materials, record details and close loops.

Sustainable living: Franklin Village in Mannheim by Sauerbruch Hutton is one of the first major socially and ecologically developed residential projects in Germany.