A CONSCIOUS TOMORROW: Cradle to Cradle
Publication date: 13.05.2025
This is an article by Rafael Vieira, translated and slightly adapted by Jan Hoffman
Internal overview of the ZIN project, renovated according to circular principles and with Cradle to Cradle certified elements.
Renovation of buildings with reused and recycled materials: a sustainable future for construction
The Cradle to Cradle (C2C) concept, developed by William McDonough and Michael Braungart, proposes a circular system in construction, where all materials can be reused or regenerated indefinitely, without generating waste. In contrast to the linear model in the material life cycle, from extraction to disposal, known as Cradle to Grave, this approach reduces the negative impact of construction and aims for a regenerative effect, which is essential in a context of increasingly evident environmental crisis.
Broadgate Exchange House in London, a building designed by Skidmore, Owings & Merrill (SOM) in 1990, refurbished in 2022 using circular principles by Piercy&Company. Various materials from the original building were reused and recycled for new uses and functions.
The renovation of buildings according to Cradle to Cradle principles is a concrete response to these issues, based on principles of sustainability, circularity and respect for the environment. Each building becomes an agent of environmental, social and economic regeneration, functioning as a bank of materials that can be recovered and reused at the end of their life cycle. The big difference compared to regular renovation or rehabilitation involves the careful selection, both at the construction and disciplinary level, of resources from demolition, industrial surpluses or waste to be recovered, and how to integrate them effectively into the design process. Each component has been designed to return to the production cycle after use, without any loss of quality or functionality. This approach also requires a paradigm shift in architecture: you build with an awareness of the life cycle of construction elements. The role of technicians is to mediate between existing resources and new ways of living, with responsibility and creativity.
University residential modules from the 1970s in Brussels, which have served as a constant laboratory for circularity, the Circular Retrofit Lab, integrating the original modular structure and incorporating reusable materials and reversible systems, designed by Kaderstudio and VUB Architectural Engineering.
Cradle to Cradle seeks sustainability and circularity in products and processes, encouraging the creation of products that can be used and reused safely, without generating waste that is harmful to the environment or human health. Reused wood, recycled flooring, reconditioned steel, old bricks or insulation made from reused textile fibres are some of the possible materials used. Sustainability thus runs through all phases of the project. It goes from planning to the end of the life cycle of the different materials. Solutions should favour reversible assembly systems, avoid composites that are difficult to recycle and adopt passive climate control strategies. Energy efficiency can be enhanced with solar panels, natural ventilation, effective insulation and vegetation that contributes to shading.
The ZIN project has transformed two towers of the former World Trade Centre complex in Brussels, dating from the 1970s and 1980s, into a multifunctional space (housing, offices and leisure) based on circular principles, with 95% of materials reused and C2C certified.
Cradle to Cradle buildings are designed to eliminate waste and pollution, ensuring that all materials can be recycled or reused at the end of their life cycle, mimicking natural processes. This methodology aims to promote a circular economy in the built environment and efficient resource management. Specific practices include the use of recycled and recyclable materials, the implementation of energy efficiency systems, rainwater collection and treatment, the creation of material passports for traceability and reuse, the incorporation of green elements and prioritising material health and social equity. Ultimately, the aim is for buildings to be demountable, recyclable, energy positive, healthy and economically viable.
The LichtAktiv Haus in Hamburg is the renovation of a 1950s house that incorporated recyclable materials, natural ventilation and maximised natural light, designed according to the principles of Active House, in line with C2C principles. This is a project by Katharina Fey and others for The Velux Group.
To find C2C products, we recommend the C2C Institute's Product Innovation Directory and platforms such as Upcyclea, Circularity Passport and Madaster, which list materials and plan their circularity. However, there are other possibilities for reusing materials in the construction process, such as the Nada Novo association, as well as the important environmental and social role of circularity. It is essential to recognise that the implementation of these principles of reuse - even if gradual or partial - is not only of technical or aesthetic interest, but is also an ethical and necessary appeal.