Experimental and numerical characterization of mycelium-based bio-composites as building insulation materials

Abstract

This thesis introduces and characterizes mycelium-based composites (MBCs) through multi scale experimental and numerical analyses. These composites combine plant aggregates with a fungal matrix, creating a natural insulation material with net-zero carbon potential. For practical applications in building envelopes, a detailed understanding of their hygrothermal properties is crucial, as thermal and moisture behaviors are strongly interdependent. An integrated analysis of heat and moisture transfer, including property measurement, correlation analysis, and simulation, was therefore undertaken. Research gaps remain in the measurement covering the spectrum of hygric behavior, in their relevance to thermal and microstructural properties, and in the development of numerical models that incorporate sorption–desorption patterns, hysteresis, and coupled heat–mass transfer. To address this, a three-stage methodology was applied. First, fabrication trials explored substrates, fungi, additives, and processing methods to optimize homogeneity and fungal growth, considering the compatibility of constituents such as the cellulose-lignin composition of the substrate, their interaction with mycelium, and the types of incorporated mycelium and additives. Second, experimental campaigns evaluated insulation performance, moisture buffering, thermal conductivity, and selected microstructural properties. Third, a coupled heat and mass transfer model was implemented in COMSOL, with sorption models calibrated using the experimental results and validated against the measured moisture buffer value (MBV), an index that quantifies a material’s capacity to moderate indoor humidity fluctuations. Both isothermal and non-isothermal simulations, including hysteresis effects, were performed. The results confirm the suitability of MBCs as sustainable replacements for carbon-intensive insulation materials such as Styrofoam. The developed fabrication practices, the obtained range of experimental results, and the highly accurate and reliable numerical model provide a foundation for future research on alternative formulations and performance predictions under diverse climatic and envelope conditions.

Date	13 Feb 2026
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Daniel Rousse (Supervisor) & Geoffrey Promis (Co-supervisor)