Sourcing good material

Builders who are guided by the prin­ciples of the cir­cular economy, urban mining and Cradle to Cradle (C2C) not only need good con­cepts and designs. They also need the right mate­rials.

Building mate­rials with C2C cer­ti­fi­cation must fulfil five cri­teria:

• They can be broken down into their com­ponent parts again without leaving any residue,
• are free from harmful and toxic sub­s­tances,
• are pro­duced as CO2-free as pos­sible (through the use of rene­wable energies),
• do not have a negative impact on the natural water balance during pro­duction
• and are manu­fac­tured in a socially respon­sible manner.

Mate­rials that fulfil these cri­teria and have already been installed in existing buil­dings can be reused (or com­posted). These com­ponents and mate­rials must be removed during dis­mantling and sepa­rated accor­dingly – keyword: urban mining. In the second step, centres are needed where these building mate­rials can be offered for reuse. If this is done regio­nally, it not only mini­mises CO2 emis­sions directly at the con­s­truction site but also during transport.

Com­ponent exch­anges and online mar­ket­places can be found here, among others:

• The mar­ket­place restado ope­rates as an online shop; the platform works tog­ether with large archi­tecture firms and project deve­lopers.
• The “urban mining hub” Con­cular, which claims to be Germany’s largest shop for cir­cular building mate­rials, emerged from restado, where the range can be searched for both indi­vidual pro­ducts and pro­jects.
• Germany-wide offers are sum­ma­rised by Bau­teilnetz Deutschland [Com­ponent Network Germany], where a com­ponent cata­logue lists offers according to dif­ferent cate­gories and also refers to regional com­ponent exch­anges.
• In addition to com­ponents and mate­rials, the portal Bau­teil­börse Han­nover [Com­ponent Exchange Han­nover] also pro­vides links to other regional com­ponent exch­anges.
• Timber com­ponents in par­ti­cular (but also offers for bricks, stone slabs and tiles) can be found at the Knapp company in Deensen, Lower Saxony.
• Anyone looking for his­to­rical building com­ponents will find what they are looking for in Marwitz, north-west of Berlin.
• Alte Zie­gelei [Old Brick­works] Lemgo also spe­cia­lises in his­to­rical building mate­rials.
• The Heritage Building Service in Lower Saxony sup­ports owners in the pre­ser­vation of his­to­rical buil­dings. It main­tains two material warehouses with a large variety of his­to­rical building mate­rials.

Building mate­rials that can be used again and again in the future are also incre­asingly coming onto the market as new pro­ducts. “The number of building pro­ducts that comply with the C2C prin­ciple con­tinues to grow. This shows us that manu­fac­turers are paying more attention to the recy­cla­bility, inno­vative strength and sus­taina­bility of their building pro­ducts,” says Peter Mösle, Partner at Drees & Sommer SE and Managing Director of EPEA GmbH – Part of Drees & Sommer. “For the con­s­truction and pro­perty industry, this means that Cradle to Cradle is no longer a niche topic but is becoming incre­asingly pre­valent in the sector.”

Manu­fac­turers are having their C2C con­s­truction pro­ducts cer­tified: The Cradle to Cradle Pro­ducts Inno­vation Institute (C2CPII) is one of the players that analyse, eva­luate and, in some cases, optimise pro­ducts in terms of their toxi­co­lo­gical pro­perties and recy­cla­bility. In order to inte­grate raw mate­rials for con­s­truction into a cir­cular economy, com­panies must also take back their pro­ducts. This can be initiated through a deposit system, for example. Other options include renting or leasing pro­ducts. In these ways, C2C is becoming a pro­mising business model: Management con­sul­tants from Accenture have cal­cu­lated that a global cir­cular economy across all sectors could generate a sales volume of USD 4.5 trillion by 2030.

There is curr­ently a lot of movement on the supply side. Some regional exch­anges have now closed again, while new ones are emerging else­where. In general, both new building mate­rials that have a C2C cer­ti­ficate and building mate­rials from existing stock are incre­asingly being offered – because demand has been growing signi­fi­cantly in the last few years. It is worth che­cking with your own architect and local trade­speople or building material dealers in good time before planning begins, to see whether there are mate­rials available locally for reuse.

Text: Lars Klaaßen, February 2024

Photo: Peter Doran / Uns­plash

About the author: Lars Klaaßen, jour­nalist, has been working as a free­lance author and editor — among others for taz, Süd­deutsche Zeitung, Deut­sches Archi­tek­ten­blatt and sci­en­tific insti­tu­tions — since 1989. He spe­cia­lises in the fields of archi­tecture and urban deve­lo­pment, con­s­truction and housing as well as energy tran­sition and climate change. www.medienbuero-mitte.de

Edi­tor’s note:
The first pro­fes­sorship for Cir­cular Con­s­truction in Germany has now been estab­lished. In December 2023, Anja Rosen was appointed pro­fessor for the tea­ching and research field of Cir­cular Con­s­truction at the Department of Building Con­s­truction at Münster Uni­versity of Applied Sci­ences.

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