The increasing demand for sustainable building solutions has directed attention toward bio-based materials, among which mycelium bio-composites (MBCs) have emerged as promising alternatives to traditional insulation materials. Grown from fungal mycelium and lignocellulosic waste, MBCs offer low embodied energy, biodegradability, and effective hygrothermal performance. This review assesses the current state of the art in MBC fabrication and hygrothermal properties, encompassing both laboratory-scale and industrial methods. MBCs demonstrate thermal conductivity values in the range of 0.036–0.06 W·m⁻¹·K⁻¹, moisture buffering capacity comparable to plant-fiber composites, and up to 70% lower embodied carbon than conventional materials. Key challenges are identified, including process standardization, scalability, and durability under real-world conditions. These composites also offer moisture buffering, compostability, and design flexibility. Moreover, recent advancements in additive manufacturing and microstructural optimization suggest a path toward broader adoption of MBCs in construction. By highlighting critical technical and scientific developments, this review identifies targeted research priorities, including the development of standardized fabrication protocols, quantitative lifecycle assessment of MBCs across varying climates, and strategies to scale up production while maintaining mechanical and hygrothermal consistency.

This study investigates the coupled hygrothermal behavior of mycelium-based composites (MBCs) as a function of their microstructural organization, governed by fungal species, substrate type, additive incorporation, and treatment method. Eleven composite formulations were selected and characterized using a multi-scale experimental approach, combining scanning electron microscopy, dynamic vapor sorption, vapor permeability tests, capillary uptake measurements, and transient thermal conductivity analysis. SEM analysis revealed that Ganoderma lucidum forms dense and interconnected hyphal networks, whereas Trametes versicolor generates looser, localized structures. These morphological differences directly influence water vapor transport and heat conduction. Additive-enriched composites exhibited up to 21.8% higher moisture uptake at 90% RH, while straw-based composites demonstrated higher capillary uptake and free water saturation (up to 704 kg/m³), indicating enhanced moisture sensitivity. In contrast, hemp-based formulations with Ganoderma lucidum showed reduced sorption and vapor permeability due to limited pore interconnectivity. Thermal conductivity varied nonlinearly with temperature and moisture content. Fitting the experimental data with an exponential model revealed a moisture sensitivity coefficient thirty times lower for GHOP compared to VHOP, highlighting the stabilizing effect of a compact microstructure. The distinction between total and effective porosity emerged as a key factor in explaining discrepancies between apparent and functional moisture behavior. These findings demonstrate that hygric and thermal properties in MBCs are governed not by porosity alone, but by the geometry and connectivity of the internal fungal network. Optimizing these structural features enables fine control overheat and mass transfer, laying the groundwork for the development of high-performance, bio-based insulation materials.

The use of bio-based building materials as an alternative to replacing concrete or insulation materials is called to become a growing trend in the construction industry. On Science direct, publications concerning “bio-based materials” have increased from 4 in 2002 to 1073 twenty years later, demonstrating a growing interest in these materials However, among bio-based materials, crop or plant-based materials are not as popular. Due to their relative novelty, little is known about their potential applications, physical characteristics, and environmental impacts. The aim of this review is to qualitatively investigate the technical and environmental viability of crop-based materials in modern building applications. The specific objectives of the study consider greenhouse gas (GHG) emissions using life cycle assessment (LCA) approaches, contribution to the circular economy, and physical and hygrothermal characteristics. Another objective is to examine the progress of crop-based materials’ R&D, current bottlenecks, and a future roadmap for their evolution in state-of-the-art renewable buildings. The paper is broad enough to capture a large readership rather than experts in the domain. The review reveals that crop-based materials have the potential to replace traditional, highly emissive building materials. They offer low environmental impacts, in all stages of their life cycle.