About Mushroom Insulation

History

• Mushroom insulation was first developed by Eben Bayer, a student at Rensselaer Polytechnic Institute, as an experiment, and then later marketed in a company he created with a fellow graduate, Gavin McIntyre. Inspired by a casual observation -- that fungus binds wood chips together when left to their own devices -- Bayer combined flour, water, minerals and mushroom spores to create a tight, compact network of mycelium and minerals. The mycelium networks of the fungus bound the other materials together. This process could then be halted and the new material molded into sheets and cut for home or commercial insulation.

How It Works

• Mycelium are composed of extremely thin filamentous structures called hyphae, which can extend to create vast, extensive networks -- usually in the soil. Fungus also secretes enzymes that break down an organic plant waste called lignocellulose. When fungus is placed in a controlled environment with organic products, such as rice or soybean hulls, it digests the waste products from those hulls while binding the material together into a cohesive mass. This active process could then be stabilized and halted, in part by thoroughly drying it, leaving the insulation biologically inert and free of allergens.

How It Performs

• When subjected to industry tests, mushroom insulation performed better against fire than traditional insulation and was on par with lumber products for resistance to flood damage and fungal growth. While the dried mycelia used for mushroom insulation is itself combustible, the organic products used as bulking agents -- such as rich hulls -- have a naturally high silica content. This silica prevents the product from burning easily. In at least one flood test, mushroom insulation absorbed less than 8 percent water -- comparable to lumber products -- while maintaining structural integrity. Surprisingly, it also resists fungal growth due to a low-level application of boride solution.

Environmental Considerations

• Mushroom insulation is constructed of biodegradable products that can be composted after use. The bulking agents are also flexible, so the components used to make the insulation can shift based on what is locally available at any particular production facility. In addition, mushroom insulation does not require a high-tech facility, petroleum products or blowing gases to produce it, unlike traditional foam insulation. However, because it is not widely available at the time of publication, it is not yet making a strong environmental impact or acting to significantly reduce the use of traditional foam insulation.