Mycostructures—growth-driven fabrication processes for architectural elements from mycelium composites

The paper discusses how characteristics of the mycelium growth process—namely different growth effectiveness depending on the nutrition content of the substrate, gradual solidification of the inoculated substrate, and bio-welding—can be a driving force for developing sustainable biofabrication processes of mycelium based composites (MBC) for architectural application. To explore this potential one-semester (12 weeks) seminar and one block seminar (2 weeks) with master-level students were held at the University of Stuttgart, and independent work within the Institute IBK2 was performed. The free experimentation with fabrication tactics resulted in the emergence of different investigation paths, tested with small-scale demonstrators, from which the most interesting three this paper presents in detail. The first is the two-phase printing process of mycelium substrate and subsidiary reusable support materials. It applied tests with the small, inorganic, loose substances (plastic pellets) extractable mechanically and meltable substances (wax) extracted by heating. The second path of investigation followed lost formworks created from hemp strings positioned inside the material. Finally, the third path is a particular case of lost formwork approach utilizing different tubular bandages stuffed with MBC and utilizing it later as a thick filament for other different form-giving deposition practices: layering, hanging, braiding, and knotting. All three investigation paths prove feasible, although their upscaling potential correlates strongly with the successful automation of the processes using CNC machines, which could provide the precision and sterility needed for this highly heterogenous and sensitive material. In addition, further developments in the material cultivation protocols are indispensable to provide a higher repetition of the results.