Anatomy of a Living Joint

From Hyphal Networks to Urban Fabrics

Abstract

Architectural joints are usually designed against nature: tight tolerances, inert adhesives, and dry, controlled assemblies. This paper explores the opposite viewpoint: a breathing joint that invites biology to do the work of connection. We present a geometry, inspired by reaction–diffusion morphologies in brain corals, that shapes oxygen exposure and moisture retention along the interface between two 3D printed mycelium–biochar elements. The pattern creates oxygen corridors for fungal respiration while carving sheltered moisture wells that stay humid longer, guiding hyphae to interweave across the seam and weld the composites without synthetic glue. We situate the work within current advancements in mycelium-based and biochar-enhanced bio-composites for additive manufacturing; materials that promise low-carbon insulation and structural performance if growth, shrinkage, and contamination are controlled (Appels et al. 2019; Aiduang et al. 2022; Yang et al. 2021). We then outline a design-led method that couples toolpath logic to biological needs, and report early observations on growth consistency and joint formation, building on prior experiments that optimized formulation, geometry, and printing parameters. For architecture, this designed metabolism reframes the joint as a controllable microclimate where geometry, material, and organism negotiate a bond.