The house that mushrooms built
© Ecovative Design

The Assignment

Last April, Sam Harrington was given an assignment: grow a house.

Mycelium, shown under an electron microscope
© Ecovative Design

Harrington works at Ecovative Design, where they create innovative and environmentally friendly products ranging from packaging to construction materials.

But grow a house?

Yes, like other Ecovative Design products, this house would be built—and grown—with the help of fungus fibers called mycelium.

Ecovative Design has discovered a process that uses mycelium to tightly bond things, like wooden boards, together. They would now apply the process in housing innovations.

The Plan

Harrington decided to build a “tiny house,” a home under 500 square feet. The tiny house movement has been growing in popularity since Sarah Susanka published The Not So Big House in 1995.

Harrington’s tiny house, like many others, would be built on a trailer so it could be moved around easily. It would also have space-saving features like a bed loft.

Harrington learned that the first annual Tiny House Fair would be held in June, 2013, and he was determined to attend with the completed tiny house in tow. So, he had to put his innovative ideas to work quickly!

Building the Frame

Harrington started the mushroom tiny house with a simple four-corner frame that marked the edges of its outer perimeter.

The house requires four posts to mark the corners, but no studs.
© Ecovative Design

Then he screwed on two parallel layers of pine tongue-and-groove boards with three-and-a-half inches of air between them. The mycelium, or mushroom mixture, will later fill this space.

There are no supporting studs in the mushroom house. The mycelium bonds the two layers of boards so tightly together that it doesn’t require the additional structural support beyond the corner boards.

Growing the Walls and Ceiling

To fill the wall cavities, Harrington and team packed layer after layer of moist mushroom mix (made from corn stalks and mycelium) into the cavities to serve as insulation.

The Mushroom® Insulation has several advantages. Since there are no studs, it is continuous, preventing colder spots in the walls that occur when standard insulation is fitted around studs. Also, the mushroom mixture even grows around and seals the electrical outlets, which are notorious for leaking cold air in tradtional construction.

Harrington and team fill the walls with the mycelium mixture.
© Ecovative Design

Each layer of Mushroom® Insulation grew for about three days and turned mycelium-white. That’s when Harrington knew that the mix was tightly fused to the pine boards.

How does your mycelium grow?
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Does the house ever stop growing? Harrington explains, “The Mushroom® Insulation slowly dries through the pine boards, so it is important not to make a structure out of plastic! The fungus eventually runs out of moisture and stops growing. But if you have a roof leak in the house, a mushroom might grow there to indicate the leak.”

(Oh, I see an added benefit of Mushroom® Insulation—surprise home-grown mushrooms!)

A tiny window in the wall shows the Mushroom® Insulation.
Ceiling tiles are made of the same material.
© Ecovative Design

The team also used their mushroom technology in the ceiling tiles. Harrington reports that the tiles have excellent acoustic properties. Plus, the mycelium material is highly fire retardant.

Future Innovations

Eventually, the team also hopes to use the mycelium to grow furniture. They have plans to create engineered-wood-type products that could be put together.

But that’s in the future. This year, they finished just in time to get to the Tiny House Fair and show the world their housing innovations.

Oh, I see—with innovative ideas, even growing a home is possible!

The first tour of the tiny house
© Ecovative Design

In this video, Harrington and Ecovative CEO Eben Bayer explain their mushroom technology and the mushroom tiny house project.

Watch this video from Derek “Deek” Diedricksen, host of HGTV’s “Extreme Small Space,” to take a tour of the mushroom tiny house.

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