Mycelium, the root-like fungal network that can be grown into panels, furniture and building components, is being positioned as a sustainable alternative to conventional materials—but its real-world viability today rests on two unresolved technical problems: it degrades when exposed to moisture, and its structural integrity and brittleness limit demanding applications. The most concrete answers to those problems are coming from targeted research, notably Newcastle University's BioKnit project and its Hub for Biotechnology in the Built Environment-linked work on dehydrated, potentially reactivatable "living" composites. Understanding both sides of that ledger is what separates a grounded material assessment from sustainability hype.
Mycelium's Promise and Practical Hurdles in Design
Writing for About Futures, Aleesha Callahan frames the material's appeal and its friction in a single breath: mycelium offers "endless innovative possibilities" in design, yet carries technical limitations that are intrinsic to its biology rather than incidental. Two properties dominate that caution. The first is water resistance—mycelium-based materials have shown "a propensity to degrade when exposed to moisture," which rules out unprotected outdoor use and humid interior environments unless that weakness is engineered away. The second is structural behavior: the material can exhibit impressive tensile strength and suit certain load-bearing roles, but its integrity is "compromised under specific conditions," and inherent brittleness in some products restricts uses demanding impact resistance and durable performance.
Addressing Water Resistance: Bioengineering and Novel Composites
Moisture susceptibility is the harder of the two constraints, because it attacks the material's fungal structure itself rather than a manufacturing variable. Callahan's reporting identifies bioengineering and novel growth and post-processing methods as the research directions being pursued to improve water repellency, though the specific techniques remain at the development stage rather than standardized industrial practice.
The clearest institutional effort in this space is the BioKnit project at Newcastle University, which explicitly aims to produce mycelium composites with improved moisture resistance—composites that combine fungal growth with textile reinforcement rather than relying on mycelium alone. Newcastle's own framing is candid that the goal is not a drop-in plasterboard substitute: "We're not trying to simply replace plasterboard panels with mycelium. We're trying to enable a different way of building that's radically more sustainable." For designers, that distinction matters—a moisture-vulnerable composite is viable today only where humidity exposure is controlled, which is why near-term applications cluster around interior linings.
