The demand for building materials has been constantly increasing, which leads to excessive energy consumption for their provision. The looming environmental consequences have triggered the search for sustainable alternatives. Mycelium, as a rapidly renewable, low-carbon natural material that can withstand compressive forces and has inherent acoustic and fire-resistance properties, could be a potential solution to this problem. However, due to its low tensile, flexural and shear strength, mycelium is not currently widely used commercially in the construction industry. Therefore, this research focuses on improving the structural performance of mycelium composites for interior use through custom robotic additive manufacturing processes that integrate continuous wood fibers into the mycelial matrix as reinforcement. This creates a novel, 100% bio-based, wood-veneer-reinforced mycelium composite. As base materials, Ganoderma lucidum and hemp hurds for mycelium growth and maple veneer for reinforcement were pre-selected for this study. Compression, pull-out, and three-point bending tests comparing the unreinforced samples to the veneer-reinforced samples were performed, revealing improvements on the bending resistance of the reinforced samples. Additionally, the tensile strength of the reinforcement joints was examined and proved to be stronger than the material itself. The paper presents preliminary experiment results showing the effect of veneer reinforcements on increasing bending resistance, discusses the potential benefits of combining wood veneer and mycelium’s distinct material properties, and highlights methods for the design and production of architectural components.

Topological interlocking assemblies (TIA) are structural systems composed of kinematically interlocking elements that rely solely on friction for stability, eliminating the need for additional connectors and enabling full reversibility. Precision in interlocking interfaces is crucial for effective load transfer. While existing research focuses on durable materials like concrete and 3D-printed polymers, less attention has been given to using biodegradable materials such as mycelium-based composites (MBCs). MBCs offer a sustainable alternative to conventional construction materials but present challenges for reversible assembly due to their non-homogeneous composition and dimensional shrinkage. To address this, we propose a method combining additive manufacturing (AM) with mycelium cultivation. A PLA bioplastic shell infused with wood particles serves as a lost formwork, which is then filled with a mycelium-inoculated substrate. The mycelium consumes the printed shell, naturally bonding the formwork and infill. The result is a lightweight, interlocking module capable of supporting compression loads while offering insulation and acoustic benefits. Given the shrinkage issues affecting interlocking precision, a study was conducted to assess dimensional variations and develop design adjustments. We demonstrate the design, production and cultivation process, as well as shrinkage control strategies. A full-scale prototype partition wall (2.40 x 1.00 m) with 112 interlocking blocks was fabricated using consumer 3D printers. Overall, the study presents a methodology for integrating MBCs in reversible architectural assemblies, enhancing reusability and extending material lifespan.