The composite material is comprised of a substrate of discrete particles and a network of interconnected mycelia cells bonding the discrete particles together. The composite material is a made by inoculating a substrate of discrete particles and a nutrient material with a preselected fungus. The fungus digests the nutrient material over a period of time sufficient to grow hyphae and to allow the hyphae to form a network of interconnected mycelia cells through and around the discrete particles thereby bonding the discrete particles together to form a self-supporting composite material. In another embodiment, the fungus is allowed to grow as a fruiting body out of the substrate and within an enclosure to completely fill the enclosure to form a self-supporting structure.