Dusseldorf Thomas Götzen pedals to the construction site in Düsseldorf’s Medienhafen on his racing bike. His dark hair sticks to his temples – the Interboden Group office in Ratingen is more than twelve kilometers away.
He took over the management of the real estate developer in 2021 from his father, the architect Reiner Götzen. Only the V-shaped concrete supports of “The Cradle”, a wood-hybrid office building, can still be seen. The building is called that because the materials used in it are to be reused in the sense of a circular economy (English: Cradle to Cradle, in short: C2C).
Götzen points to the foundation “the core is made of recycled concrete”, in a few weeks it will be “really exciting”. Then the modular prefabricated wooden structure should arrive. With the help of the digital planning method BIM (Building Information Modeling), every millimeter was precisely measured.
“Concrete can be corrected, but a wooden structure has to fit perfectly,” says the 39-year-old. With wood from regional forestry instead of reinforced concrete and a photovoltaic system on the roof, CO2 emissions are reduced by around 40 percent compared to a conventional office building, according to environmental consultancy EPEA for Interboden. That is 1900 tons and corresponds to nine million flight kilometers.
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Interboden has set itself the goal of using recyclable – i.e. pure and separable – materials without toxins. Because later on, “The Cradle” should not be a case for the landfill, but a modern raw material warehouse.
The real estate developer wants to establish more sustainability in the industry.
(Photo: INTERBODEN)
After all, Götzen, father of three children, knows very well that the construction and building industry is one of the biggest climate sinners. His family has been in the construction industry since his grandfather Heinrich opened an architectural office in 1950. The construction industry currently causes around 40 percent of energy-related CO2 emissions worldwide and is responsible for more than half of global waste and resource consumption. The production of concrete and cement in particular consumes large amounts of non-renewable resources.
“Instead of producing new building materials and blowing tons of carbon dioxide into the air, we should reuse them as often as possible or replace them with renewable raw materials such as wood,” says Jan Grossarth, Professor of Bioeconomy and Circular Economy at Biberach University. In order for this to succeed, the demolition or dismantling must already be included in the design of a new building and be digitally accessible. Not a matter of course in an industry in which some people still plan on paper.
Building materials are linked to commodity exchanges
It’s different with “The Cradle”: Whether terrace coverings, sanitary tiles, window elements: all of the building materials carefully selected according to C2C criteria over many years of preparatory work are recorded in a digital material pass and on the “Madaster” building platform. This makes information such as the origin, quality and ecological balance of the components, including their “circular” and financial value, transparent at the click of a mouse.
Because Madaster, a digital register for building materials, is linked to raw material exchanges and shows the current material value in real time. “This is highly attractive for investors,” believes Interboden Managing Director Carsten Boell, who is responsible for the office project. Because in the “digital twin”, a virtual representation of The Cradle created in BIM, it is also evident how much gray energy is hidden in the building. This refers to the emissions generated during the manufacture and use of the building materials.
>> Read about this: These building materials swallow CO2: How the construction industry could go green
Real estate like “The Cradle” are financial products, says Boell. Since the introduction of sustainable ESG criteria, investors have been paying close attention to “avoiding taxonomic risks” and investing primarily in buildings that are not threatened with hefty CO2 taxes or demolition due to high renovation costs.
All materials in “The Cradle” have been checked for their usability.
(Photo: INTERBODEN/HPP Architects/bloomimages)
With a 40 percent lower carbon footprint, Götzen expects a “significant increase” in property value. Half of the office space is already rented. Götzen’s father, who signed the company over to his son in 2022, had approved the almost three-digit million project, although we “had to work hard to make it profitable,” says Thomas Götzen.
For example, because the supply of recyclable materials in Germany is still scarce and therefore expensive – just like skilled workers. In addition, there would be the “immense bureaucratic effort”. Interboden and the commissioned architectural office HPP Architekten had to keep looking for replacements because standards for recyclable materials were missing, as was the experience of the approval authorities.
Götzen would have liked to use more recycled concrete than just for stairwells and elevator shafts. But that was not allowed in 2017, when work on “The Cradle” began. According to the EPEA, a total of 97.7 percent of the building is recyclable and therefore recyclable, but this also includes downcycling, the conversion to a lower-quality end product. Landfilling and thermal recycling, i.e. burning materials for heat, is only 2.3 percent.
“Some people still plan on paper”
For the conservative and little digitized construction industry, in which “circular construction” or “urban mining” are foreign words, such numbers are “very impressive”, says Grossarth. Normally, valuable raw materials would be wasted in road construction after demolition. “Terrible downcycling,” says the professor. In addition, an “extremely bureaucratic approval system swallows up innovation and creativity”. So far, the “sustainability mindset” can only be found among institutional real estate investors, not in the much larger area of single- and multi-family houses.
This makes projects like “The Cradle” all the more important. They showed what is possible and inspired imitation. A visit to the C2C-style town hall in Venlo, the Netherlands, also brought Thomas Götzen to the circular economy in 2017. Then he knew, “that’s really cool, we should do that too”.
At first, Götzen did not want to work in his father’s company. Instead of becoming an architect, the junior studied international management in Innsbruck and did his doctorate at the Chair for Entrepreneurship at the University of Liechtenstein. Not least because the passionate alpinist could hike and ski there. In 2013, Thomas Götzen joined the family business and founded the start-up Animus in the same year, which connects tenants, owners, project developers, property managers and service providers “in one neighborhood app”.
For Götzen, the Cradle is a “logical consequence of the company’s history” that combines pioneering spirit and sustainability. His father built Germany’s first solar settlement back in the 1990s. In the future, Götzen wants to continue working on “modern, livable and ecologically managed quarters”. And he wants to make Interboden the “most digital provider for residential and commercial use in the region”. An achievable goal.
More: Virtual buildings, digital raw material stores, wood hybrids: This is how construction will work in the future