Why mushrooms could be the future of environmentally sustainable building materials

Originally published February 28, 2020.

As the construction industry struggles to deal with its impact on the climate, a new generation of people with big ideas are looking for alternative materials to build with.

Phil Ayres, an architect and associate professor of architecture in Copenhagen, says the future of building materials may not be high-tech polymers or specialty metals, but mushrooms.

Ayres joined Spark host Nora Young to discuss how he and his team are investigating how mycelium – the fibrous network that exists beneath a mushroom – could be used as an environmentally sustainable building material.

What’s wrong with building with old bricks and concrete? What problem are you trying to solve?

We are really interested in the fact that we have real societal problems in terms of building requirements. We have growing populations. We have rapid urbanization. And we’re starting to realize that the amounts we need to build really aren’t sustainable.

We understand that current construction practices and methods, especially with materials like concrete, actually have a negative impact on the environment. Concrete by itself is not particularly a high-impact material, but the quantities in which we use it make it a major contributor to CO2 and a major sink for resources. This actually leads to shortages of raw materials such as sand. So we have real pressure to try to find viable alternatives.

And so when it comes to biological materials, that’s where this project starts to contribute.

Phil Ayres, an architect and associate professor of architecture in Copenhagen, and his team are studying how mycelium – the fibrous network that exists under a mushroom – could be used as an environmentally sustainable building material. (Hayden Zakrisson-Ayres/Supplied)

What about the mycelium that makes it a good building material?

The mycelium is freely available and binds to cellulose-rich waste sources.

It grows incredibly fast and actually bonds to whatever substrate you combine with it. You can grow it to shape it – in a way you might understand much like how we might pour concrete to shape it. We can do the same with the mycelium, but grow it in five days to two weeks.

It also has very little impact on the environment. In fact, it could be understood as positive for the environment because you use these waste streams.

The way this is currently being explored, in more experimental practices, is to kill the mycelium. So you basically cast it in blocks and bricks and then assemble it from there. One of the things that we’re doing in our research is actually entertaining the idea of ​​growing things monolithically, which requires us to keep the mycelium alive.

Another reason we need to keep the mycelium alive is that our partners at the UK-based Unconventional Computing Group are looking to functionalize it and turn it into a rudimentary sensing and computing device..

What do you mean by growing things monolithically?

Rather than thinking of our build as a collection of discrete pieces, we actually think of growing entire buildings at once.

Mycelium is a fibrous network that begins to grow through the substrate – such as sawdust, straw, hemp and coffee grounds – and as it breaks down and actually binds to that substrate.

A preliminary study of Kagome weaving production. (FUNGAR/CITA)

This kind of role also requires thinking about methods to be able to retain this substrate and allow the mycelium to propagate on it. And that’s where we’re looking at using woven scaffolding as a way to essentially create a framework and reinforcement that stays in place, but also to act as a sort of mold for the mycelium.

What would this framework of mycelium look like?

We have a very specific approach to this, which is to use an ancient weaving technique called Kagome weaving, this weaving is basically a tri-axial weaving system.

One of the really interesting aspects of this method is that there are very clear principles to be able to control the form. And so using these principles, we can create very complex morphologies using very simple methods.

We basically construct a support from Kagome weaving. It’s like a double-skinned basket, which you would then fill with the substrate, which is inoculated with the mycelium and grows over a period of time.

What are some of the real challenges to making this work?

The main challenge for us is this monolithic growth objective. Most of the cultivation we see in the industry occurs under very controlled and sterile conditions. Current methodology, in terms of mycelium production, relies heavily on working in sterile environments.

The fungal material would produce significantly less CO2 when created, Ayres said. (FUNGAR/CITA)

As we begin to think about growing in architectural scale, this may need to be questioned. And part of our initial work is really trying to see how we can try to promote mycelium growth under non-sterile conditions.

The other interesting challenge, from an architectural point of view, is how architectural scale, features and spatial organizations might impact the computational capacity of mycelium.

Written by Adam Jacobson. Produced by Nora Young. The questions and answers have been edited for length and clarity. To listen to the full interview, listen to the player at the top of this page.