Engineering Sustainable Solutions: Mycelium Insulation, an Environmentally-Friendly Alternative to Polystyrene

The United Nations has identified seventeen Sustainable Development Goals to protect our planet and ensure that all people are able to lead healthy, prosperous lives. Goal 12, “Responsible Consumption and Production,” aims to create and foster eco-friendly practices and products that can help end the environmental degradation of our planet. Devising and promoting green customs and goods can reverse decades of air, water, and land pollution, not only improving the planet but the lives of all human beings.

The construction sector is in dire need of innovative, earth-friendly products and building practices. Engineering sustainable materials by efficient use of natural resources is key to ensuring the planet is protected and that future generations are provided for. Current statistics paint a bleak picture, so it is crucial to take action. Up to 30% of all building materials end up as waste (Osmani, 2011), with debris from construction estimated to be approximately one-quarter of the national U.S. waste stream (BTS, 2016). Annual waste from construction is expected to reach 2.2 billion tons globally by 2025 (TMR, 2018). Hazardous waste from construction often includes lead, mercury, fluorescent bulbs, and insulation (CMEG, 2021).

Polystyrene insulation is one of the most commonly used forms of insulation, and is extremely toxic. Polystyrene foam contains the chemical styrene, which has been linked to cancer, hearing and vision loss, impaired memory, and dysfunction of the autonomic nervous system (Lucas, 2014). It is non-biodegradable, highly flammable, and takes 500 years to decompose (Colgate University, 2011). Additionally, polystyrene manufacturing contributes to global warming because it involves the use of hydrochlorofluorocarbons, which destroy the earth’s ozone layer (CEHN, n.d.). Polystyrene fills 30% of landfills globally (Eco-Friendly Habits, n.d.) and comprises 90% of all marine debris (EPE, 2019).

It is critical to create an environmentally-friendly equivalent to polystyrene foam. Mycelium, the filamentous root system of mushrooms, has been proposed as one such alternative. A network of branched, tubular fungal threads, this material is non-toxic, fire-retardant, and poses no health risks to humans. Mycelium can be cheaply manufactured without use of hydrochlorofluorocarbons or other chemicals that contribute to global warming. When the material is no longer needed or useful, it is easily biodegradable and can be returned to the Earth without any deleterious effects. Although mycelium insulation is environmentally safe and cost-effective, it is important that the insulation is effective.

To this end, I created homemade mycelium insulation (Fig. 1) and compared its efficacy against polystyrene insulation. To construct this insulation, I prepared a mixture of 95% hemp fragments (also inexpensive and fully biodegradable) inoculated with 5% mycelium. This mixture was combined with water and flour, activating mycelium growth. After the material was stored out of sunlight for five days, additional flour was added and molds were filled with the mixture. After an additional five days, the insulation panels were removed and heated to cease further growth.

Six panels of mycelium, and of two common brands of polystyrene insulation, were used to create three small “houses.” To compare the efficacy of the insulations, the houses were tested in both hot and cold environments, with a thermometer placed in the structure to measure the internal temperature. Mycelium insulation was, in fact, found to be a much more effective insulator than polystyrene, transmitting heat twice as slowly as the traditional materials. And, when breaking strength was tested, the mycelium panels were comparable to the polystyrene panels.

In addition to being an effective, environmentally-friendly insulation, mycelium is also straightforward and inexpensive to manufacture. Therefore, its production can foster economic opportunities, especially for those in developing countries. Because of this potential for financial growth, the production of mycelium can also help meet several other UN Sustainable Development Goals; including Decent Work and Economic Growth and Reduced Inequalities. Mycelium insulation is a prime example of solutions we can find to world-wide problems through engineering.

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