Carlo Ratti Associati grows architectural structures from mushrooms

Mycelium is one of nature’s most fascinating tools. Making up the fibrous root of fungi or fungus-like bacterial colonies, mycelium acts as a sort of 'wood wide web' in nature - connecting the roots of plants to transfer nutrients. What’s more, mycelium feeds off organic compounds, and has the potential to decompose pollutants.

Architects today are discovering that mycelium has the potential to be a sustainable, sturdy and infinitely flexible building material. In addition to offering a sustainable alternative to plastic and styrofoam packaging, mycelium can also be grown and processed to build into furniture and architectural structures.

As part of this year’s Salone del Mobile in Milan, innovation and design firm Carlo Ratti Associati presented an exhibition titled The Circular Garden in a bid to draw attention to the benefits of mycelium. Set in the stunning botanical garden at the Brera Design District, the exhibition comprised a series of arches made almost entirely out of the material.

The design team at CRA talks to STIR about their process, and offers their perspective on the future of mycelium in architecture. The following interview has been edited for length and clarity.

Avantika Shankar (AS): How is mycelium grown?

Carlo Ratti Associati (CRA): For our installation, the entire growth process took only about six weeks. We start with an organic substrate as a nutrient - for example, sawdust, hemp, hay or other agricultural waste. The substrate is then placed into a mold and inoculated with the mushroom spores. As the roots develop, the mycelium fills the available space and solidifies. Once this process is completed, the mushrooms are dehydrated at high temperatures, leaving behind a durable organic material.

AS: Why is mycelium not more commonly used as a building material?

CRA: Because it is not yet resistant enough for buildings. It is a very new material that cannot be compared to stone or wood in terms of its construction potential. Our installation experimented by using mycelium for unprecedented dimensions, but it managed to do so by relying on a structure that uses compression: catenaries. Before mycelium can be used as a material for larger buildings, there is still some experimenting and research to do; our installation was a part of this process.

AS: What are some of the ways in which it can improve our architectural constructions, besides making them more eco-friendly?

CRA: First of all, I think greater sustainability is one of the most important innovations needed in the construction industry. Aside from this, mycelium has many interesting aspects. It is simultaneously resistant and light-weight. It also is quite durable and water resistant, which is why it has been used in packaging. We were also interested in mycelium from an experimental design point of view. Nature is a much smarter architect than us. As we continue our collective quest for a more responsive 'living' architecture, we will increasingly blur the boundaries between the worlds of the natural and the artificial. What if tomorrow we might be able to programme matter to 'grow a house' like a plant? For us, Milan’s amazing botanical garden, in the centre of the city, seemed the ideal place for such an experiment.

AS: Why did you choose to work with arches?

CRA: In terms of the arches, the form was necessary in order to create self-supporting mycelium structures on such a scale. We took inspiration from the great Catalan architect Antoni Gaudí. It was he, while designing the Sagrada Familia in Barcelona, who resurrected the 'inverted catenary' method pioneered in the 18th century by polymath Giovanni Poleni. According to this method, the best way to create pure compression structures is to find their form using suspended catenaries and then invert them. The same applies to the Circular Garden, where the catenaries composed a series of four architectural 'open rooms' scattered throughout the garden. These rooms in turn served the practical purpose of showcasing the work of global energy company Eni, our partner for this installation, in the circular economy.

AS: What are the future projects that you are working on?

CRA: In Singapore, we are working on the design of one of the tallest skyscrapers in the city along with BIG-Bjarke Ingels Group, with a tropical forest at its core, for CapitaLand. In Brasilia we are expanding on the great master planning work of Oscar Niemeyer and Lucio Costa for Terracap's Biotic, with a new tech and innovation district on the edge of the Cerrado. We are also part of the winning team for the Italian Pavilion at the Expo Dubai in 2020. Carlo Ratti will be a chief curator for the 2019 Bi-City Biennale of Urbanism\Architecture in Shenzhen, China, the only biennale in the world to deal with urbanisation as a fixed theme. The curating team's proposal for 2019 aims to critically explore the impact of digital technologies on communities and urban space, with a particular focus on artificial intelligence.