What if building materials became nutrients for biological or technical cycles? Cradle-to-Cradle thinking proposes re-designing building materials so they can be reused or repurposed after they are reclaimed from buildings, creating value and products out of used material. Materials could be biodegradable or endlessly recyclable – resources that are used and reused rather than discarded and then extracted or produced anew.
Instead of just the cyclical logic of recycling, materials could flow back into other cycles of production, exchanging between biological and technical loops. Building materials that break down into agricultural and industrial nutrients would help eliminate waste. Textiles or fiber panels can be designed to biodegrade so that they can be reused as nutrients. Other materials like glass and aluminum can be designed to be recycled multiple times, though the energy intensity of the recycling process needs to be taken into account. Cycling can work in both directions: just as construction components could be transformed into agricultural nutrients, packaging, industrial, or agricultural byproducts could become building materials.
At the 6th LafargeHolcim Forum for Sustainable Construction, Michael Braungart, Professor of Process Engineering at Universität Lüneburg, Germany explored the theme of “Be Good – Not Less Bad” in his keynote address in the concluding session. Cradle to Cradle (C2C) is a design concept developed in the late 1990s by Michael Braungart and the American architect William McDonough. It postulates a circular economy that goes beyond recycling as we know it today. “Let’s make architecture which supports life instead of minimizing the damage!” he said.
Under C2C no waste is generated that must be discarded; rather, all resources used, production materials, and products are kept in a continuous cycle. C2C requires rethinking at all levels. All the energy needed comes exclusively from renewable sources. Production is done using either organic materials that can be returned to the biological cycle at the end of their useful life or non-organic or synthetic materials that can be completely returned to the technical cycle. In this way, no waste Cradle to Cradle is generated, and further natural resources need not be exploited to replace discarded materials.
Strategies to re-materialize construction
As the key input to the Forum, the publication 22 Propositions offers strategies for both the material supply chain and material use in buildings. The propositions aim to “re-materialize” construction by rethinking the building material cycle from extraction to processing, design, transport, installation, maintenance, and removal.
The Materials Book to be published by Ruby Press Berlin in late 2019 will feature the essence of 22 Propositions as well as a selection of additional proposals to re-materialize construction derived from the findings of the Forum.