Eine betonartig aussehende Mauer ist zu sehen, aus der im oberen Bereich dünne, ineinander geflochtene Holzstreifen herausragen.

Mushrooms instead of concrete: innovative biomaterials enable sustainable construction


Author: Tina Walsweer

When we talk about cutting CO2, we usually think of green electricity or transforming transport. However, a less obvious area – the building sector – offers huge potential for savings. A Kassel University researcher wants to combine biomaterials with digital manufacturing technologies and make them available for architecture.

When combatting climate change, we should not lose sight of one very important causal link: the construction industry. This sector alone accounts for almost 40% of global CO2 emissions. In view of the growing world population and the corresponding demand for living space, this figure is likely to rise even further – the construction sector, though, also offers huge potential for savings. "The level of digitalization in the construction industry is still quite low compared to other sectors," reports Philipp Eversmann, architect and professor at the University of Kassel, where he is head of the Department of Experimental and Digital Design and Construction. "The construction industry is virtually predestined to tap into enormous CO2 savings potential as a result of new technologies and manufacturing processes. However, this calls for a radical shift in building materials towards renewable resources and the transition to a circular economy."

Eversmann has a clear vision of which new technologies could be the key to reducing greenhouse gases. His main focus is on digital design, robotic manufacturing techniques, and biomaterials that absorb CO2 during their growth process. However, anyone who thinks that wood might be the most suitable renewable raw material in this context would be very much mistaken. "I have been working with wood as a building material for many years. However, it takes decades for a tree to grow to the point where it can be used as a building material. That's why I asked myself whether other materials could be used that don’t take so long to grow, can be produced almost anywhere, and can be shaped into any form you want."

Alternative biomaterials open up completely new potential here. In contrast to conventional manufacturing techniques, their growth processes can also be integrated into the design and production process. This makes it possible to grow the material into certain shapes, adapt the material properties, or produce reinforced composite materials. Fungi are a good example of this. More precisely, their root network, the mycelium. Under laboratory conditions it is possible to precisely control and monitor the growth of mycelium. The growth process only takes a few weeks – and as the fungal mycelium grows on a spreadable substrate, there are virtually no limits to its shape. "This opens up completely new design possibilities," explains Eversmann, "but also requires a lot of knowledge that we first have to acquire."

In einer Petrischale ist ein wachsendes weißes Pilzmyzel zu sehen. Die Petrischale wird von zwei Händen gehalten.

The new biobuilding materials start with the fungal mycelium, which the researchers first cultivate on a culture medium.

Zwei behandschuhte Hände sind zu sehen, die hellbraune kleine Fasern zwischen vertikale, horizontale und diagonale helle Holzstreifen legen.

The researchers fill a mesh of thin strips of wood produced by a robot with a mixture of hemp fibres and fungal spores. After the growth phase, the mycelium is dried and hardens in the specified mould.

Es ist zu sehen wie zwei behandschuhte Hände einer Person im weißen Kittel eine geschwungene sechseckige Form mit bräunlichen Hanffasern befüllen.

The mixture of hemp fibres and fungal spores can be filled into any shape.

Zwei Personen in Ganzkörperanzügen stehen an einem Arbeitstisch in einer Laborumgebung, die durch silberne Folie von der Umgebung abgetrennt ist. Sie arbeiten an einer Form auf dem Tisch.

After being placed in the moulds, the mushroom mycelium grows into a compact mass in the incubator under optimum conditions. A subsequent drying process prevents further growth.

Eine wellenförmige Wand ist zu sehen aus der im oberen Bereich dünne Holzstreifen rausragen.

The new biomaterials make it easy to produce components in any shape. The woven wood gives them the necessary stability – similar to reinforcing steel in reinforced concrete.

First to the grassroots, then into practice

However, as research in the field of ecologically compatible materials is still mostly in its infancy, Philipp Eversmann wants to focus initially on basic research. He believes this is the only way to expand and further professionalize existing research in the field of sustainable construction. "For such an innovative and, of course, unusual research project, I needed a sponsor who would be willing to support me over the longer term," reports Eversmann. "The Volkswagen Foundation's Momentum Initiative offers exactly the right framework for this." Via this program, the Foundation supports scientists in an early phase after taking up their first tenured position, enabling them to explore opportunities to further develop the content and strategy of their professorship.

Eversmann has settled on a three-part research strategy. Firstly, he and his team want to test and optimize design and manufacturing processes with living materials under laboratory conditions. The focus here is on individual design options in terms of aesthetics, performance characteristics and source material (e. g. algae, microbes, etc. in addition to fungal mycelium). In a further step, he wants to concentrate on design and manufacturing processes using waste materials in order to create circular systems. To this end, he wants to use plant and agricultural waste, the remains of shellfish, and waste wood. In the third step, the researcher wants to investigate the bonding of materials. This is because the use of new types of materials requires new types of bio-bonding systems that can withstand structural, physical, and production-related requirements such as bio-welding or form-fit joining.

Ein Roboterarm ist in einer Laborumgebung zu sehen. Er schweißt Holzstreifen auf eine große Platte.

The researchers combine robotics and biofabrication in their own laboratory. Only if the components can be successfully scaled up from laboratory scale to large-scale production the construction industry can utilise the technology in a meaningful way.

Nachaufnahme von einem Roboter, der dünne Holzstreifen auf einer Platte in einem geometrischen Muster verschweißt.

Scaling up from laboratory scale to large-scale production is a basic prerequisite for the technology to be accepted in practice. The close-up shows the welding technology that the researchers had to develop specifically for their novel biomaterials.

High-tech for scalability

"We have to break through technological barriers because biofabrication processes have unique technical requirements," explains Philipp Eversmann. For his three sub-projects, he wants to develop a new robotic biofabrication infrastructure at his chair. In addition to acquiring biolab equipment such as a cleanroom area and a growth chamber, he plans to develop modular software and hardware for design and production, for example to predict and specifically program material behavior using simulations and machine learning.

"The requirements for sustainable architectural applications are much more demanding, as the entire life cycle must be considered, and biomaterials are subject to a natural regeneration process. In our research laboratories, we investigate this on various scales up to 1:1 prototypes and establish contact with industry at an early stage in order to create scalability for large applications." Eversmann wants to make the results of his research available to other researchers in the form of publications, databases, open-source tools, and software projects. The aim is to increase the number of theories, applications, innovators, and experiments over the long term in order to advance methods for sustainable digital manufacturing in the field. "We want to make sustainable biomaterials available to practice as quickly as possible wherever alternative building materials are urgently needed," summarizes Eversmann.

Prof. Philipp Eversmann ist im Dreiviertelprofil zu sehen. Er trägt einen schwarzen Pullover und befindet sich in einem Arbeitsraum.

The Head of the Department of Experimental and Digital Design and Construction, Prof Philipp Eversmann.

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