Exploring Multi-Materiality: challenges and potential pathways for scaling up 3D printing of biomaterials

Large-scale additive manufacturing is transforming architecture, design, and construction. However, the development of sustainable biomaterials for 3D printing remains in its early stages. Yet, due to its versatility, additive manufacturing promises to address challenges of resource scarcity and ecological disruption and calls for a paradigm shift in material use in architecture. While industrial materials like plastics, metals, concrete, and clay have reached market maturity, biodegradable alternatives such as plant fiber composites, starch-based bioplastics, and sawdust pastes remain largely experimental. These sustainable materials struggle with limited performance, scalability, and durability, restricting their application in large-scale 3D printing. Additionally, unlike conventional materials with established knowledge bases, biomaterials require new research frameworks, further delaying their adoption. This paper explores multi-material strategies as a solution to these challenges, leveraging complementary material properties to enhance performance and sustainability. Biocomposite thermoplastics for example provide immediate structural integrity, while upcycled biodegradable materials offer carbon storage and environmental benefits. Two approaches are introduced: the "intertwined" method, where fragile biodegradable materials adhere to robust biocomposites, and the "interwoven" method, where materials are layered to combine strengths. These strategies demonstrate potential solutions to the structural and processing limitations of biomaterials. Scaling up biomaterial-based 3D printing requires advancements in fabrication technology, regulatory support, and a shift in architectural thinking. Multi-material approaches present a viable pathway to overcoming current limitations, fostering innovation, and expanding the role of sustainable materials in additive manufacturing. By embracing these strategies, architecture and construction can move toward more scalable, durable, and environmentally conscious 3D printing applications.