Mycelium: alternative sustainability for construction

Mycelium has only recently been proposed as a building element and has been used as thermal or acoustic insulation for cladding panels or blocks, among many other possible uses. The laboratory tests and certifications obtained give it credibility as a building element and affirm it as a capable alternative to conventional solutions. It stands out as a sustainable and innovative material in construction and architecture.

What is mycelium? Mycelium is the vegetative structure of fungi, formed by a network of underground filaments called hyphae. Mushrooms, the best known part of fungi, are their visible and reproductive part. Mycelium can be cultivated in different shapes and sizes, making it versatile for various applications. Its production involves creating an organic substrate from agricultural waste and by-products such as rice or cotton seed husks, wood shavings or sawdust, corn stalks and others.

The organic substrate is steam pasteurised and nutrients, a small amount of water and fungal spores or traces of mycelium are added. Next, the mixture is placed in a mould and left to stand in an unlit place. Within four days to two weeks, it is observed that the mycelium has grown and aggregated the substrate to the size of the mould. Heat is then applied to stop the growth of the mycelium, killing it in the process.

Depending on the species of fungus used, final product varieties with optimised performance and fire-retardant or dielectric behaviour are achieved. The mycelium transforms agricultural waste into a resistant, light and biodegradable material that can be used in construction panels, building blocks and even furniture. It is this finished product, with good resistance and durability indicators, that can be used in construction. Its capacity for acoustic and thermal insulation, as well as being fireproof, makes it an ecological alternative to conventional elements and materials such as concrete, extruded polystyrene (XPS) or sprayed polyurethane.

As a building material, it requires little energy to produce, helping to reduce carbon emissions. Because it is natural and compostable, the use of mycelium reduces environmental impact, promoting the circular economy and sustainability in architecture and construction. It derives from the use of agricultural waste and by-products in an organic aggregate, i.e. it is a product of waste recycling. It has no reuse potential, degrading naturally when deposited. When placed in compost or wrapped in organic matter, it degrades within a month and, even if it cannot be turned into a specific reusable product, it can re-enter the production cycle as compost.

Since 2007, Ecovative Design, a US company, has been developing alternatives to polystyrene and polyethylene in packaging and construction with mycelium solutions developed using agricultural and industrial waste. Its products include the Mushroom Insulation and Acoustics solution, Mycofoam, with cradle-to-cradle certification, i.e. products with circular potential that can be recycled or reused indefinitely, reducing environmental impact. Mycofoam, for example, has no potential to produce global greenhouse gases in its manufacture or life cycle, apart from the residual production of CO2 from the fungi used. Companies such as Italy's Mogu share the Ecovative Design premise, as does Mykor, which has a production unit in Montemor-o-Novo, Portugal. Aesthetically appealing and environmentally responsible, mycelium is a credible alternative for sustainability in construction.