We think of mushrooms as food. But mycelium-based blocks could be the future of construction
- Written by Kumar Biswajit Debnath, Chancellor's Research Fellow, School of Architecture, University of Technology Sydney
When mushrooms make the news, it’s often for grim reasons – a mysterious poisoning, toxic species in the bush, or high-profile court cases.
But the mushroom itself is only the fruit body. Beneath every cap lies the real organism: a hidden network of white threads weaving through soil and wood.
And that underground network, called mycelium, may help solve some of our biggest climate and waste problems.
In my research on building materials, I focus on improving the durability of mycelium-based materials for construction purposes. So what exactly is mycelium, and how can we harness it for various materials?
Mycelium is everywhere
Mycelium is the living body of a fungus. It grows as thin, branching filaments known as hyphae, which spread out in all directions in search of food.
In a forest, these threads help break down leaves, logs and other organic matter, known as biomass. This turns waste into nutrients that trees and plants can use again. A single mycelial network can spread across metres of soil, and sometimes much farther.
Importantly, mycelium is everywhere. It thrives in leaf litter, compost piles, mulch, crops after harvest, and even in the dead wood under our feet. We usually never see it, yet it’s one of nature’s most powerful recyclers.
A living glue
We can also use its unique features in the lab to create composite materials. Because mycelium grows by binding itself to whatever it feeds on, it naturally forms a kind of living glue. As the fibres spread, they wrap around particles of sawdust, straw, or other agricultural and industrial biomass waste, locking them together.
After a few days, this mixture becomes a lightweight but solid block. If we then stop the growth and eventually “kill” the fungi with heat, the block still holds its shape – no machinery, no plastics, and very little energy required.
All this makes mycelium very appealing in materials science. It grows at room temperature. It is shaped inside a mould. And it produces structures that are breathable, biodegradable and fire-resistant.
For designers, architects and engineers, mycelium offers a rare combination: organic material that can be grown to order.
Although the field is still young, mycelium-based materials are emerging in several areas, such as alternatives to polystyrene in packaging, alternatives to synthetic insulation panels, acoustic panels for reducing echo in noisy spaces, and even leather-like materials.
Mycelium has also been used in construction prototypes where architects have built temporary structures using blocks grown from plant waste, highlighting how construction might one day include “grown” components.
More work to be done
These examples show the versatility of mycelium, but also its limits. Mycelium-based composites – often called MBCs – are not yet strong enough to replace bricks or most plastic parts. They absorb humidity unless they are treated. They decay outdoors without protective coatings. Growth time and organic characteristics also makes large-scale, uniform production difficult.
My research group focuses on improving the durability of mycelium-based composites for building applications – predominantly for passive cooling – while maintaining their environmental benefits.
To improve the durability of a mycelium composite block, we’re exploring several routes.
First, there’s natural reinforcement – mixing fibres such as hemp, flax or other agricultural, industrial and construction byproducts to improve strength while keeping the material biodegradable.
Mycelium-based composite insulation panels, made with Australian reishi fungi and hemp.
Kumar Biswajit Debnath/UTS
Adding a protective coating is another option. If we can add natural waxes, oils or mineral layers, the materials could resist moisture without making the material toxic or non-compostable.
We’re also harnessing artificial intelligence to adjust temperature, humidity and nutrient sources for growing the blocks, to see if we can grow materials that are more uniformly dense and have better passive cooling and structural performance.
Not every method works. Some coatings trap moisture, which can weaken the material. Some fibres have slow growth. In other cases, the material becomes too brittle or too spongy. But each trial teaches us more about how fungi build their networks – and how we might guide them to build stronger ones.
Our broader goal is to create bio-based materials that can withstand real-world conditions: weather, load and time. If we can do that, mycelium-based composites could reduce the amount of plastic in packaging, offer low-carbon alternatives in construction, and push designers, architects and builders to think beyond what can be machined or moulded towards what can be grown.
A future for fungi
For now, mycelium-based materials aren’t a magic solution. They can’t yet replace most metals, concrete or high-performance plastics, and outdoor durability is still a significant hurdle.
Uniformity is challenging to achieve because mycelium is a living organism rather than an industrial polymer. And, as with any new material, standards and regulations take time to develop.
Still, the pace of discovery is fast. Researchers are exploring ways to tailor mycelium by feeding it different types of waste or combining it with plant fibres. Others study how living mycelium might one day repair cracks on its own or cool down buildings without using extra energy.
In the long term, we may see hybrid building components – part grown, part engineered – where mycelium-based composites provide insulation or acoustic performance inside a stronger outer shell.
The mushroom may be the part we recognise, but it’s the hidden fungal network underground that could shape the next generation of sustainable materials.
Authors: Kumar Biswajit Debnath, Chancellor's Research Fellow, School of Architecture, University of Technology Sydney
