Regenerative Retrofitting Via Ecologically Active Soil Structures

“'Living roofs', 'green' walls, garden bridges and overpasses… In an increasingly lifeless world of concrete, glass and brick, we are feverishly inventing ever more imaginative ways to bring chlorophyll into our polluted urban lives”

Yet the challenge of adding green areas into the built environment remains: how can this be achieved in a regenerative and innovative way? Inspired by recent studies, in this Centre for Regenerative Design & Engineering for a Net Positive World (RENEW) Summer Bursary Project, we aim to explore the potential of retrofitting existing buildings through aerial additive manufacturing technologies using ecologically active soils.

Our project envisions using automated drones to apply soil layers capable of bearing seeds, encouraging growth under optimal environmental conditions. Thus, the proposed idea would represent a self-evolving net-positive solution. Additionally, it would bring “chlorophyll into our polluted urban lives”, enhancing the relationship between humans and nature.

It is estimated that 80 % of the buildings that will exist in 2050 have already been built. Unfortunately, most of them perform poorly in terms of energy efficiency and do not comply with net-positive solutions. Therefore, our priority as engineering/architectural researchers must be to develop solutions to regenerate our existing built environment. Natural soil is a low-embodied energy, recyclable, and healthy material that has been used for millennia in our buildings, following vernacular traditions and sustainable principles. When ecologically active, it can foster plant growth, offering a path to retrofit buildings that enhance thermal insulation, expand green urban surfaces, improve air quality, and elevate aesthetics and occupant well-being.

What soil types, seeds, environmental conditions, and material application techniques (i.e., 3D printing, extrusion, or spraying) are best suited for aerial retrofitting of existing buildings?