Insulating your home with...mushrooms?

RPI E-Team Ecovative Design challenges the norm in the building industry

Open up the walls of just about any new home and you’ll find the same thing: two sheets of plywood sandwiching an insulating foam core. Known as Structural Insulating Panels, or SIPS, the approach is gaining popularity in the building industry because it’s cheap and effective. Unfortunately the foam insulation in SIPS is also environmentally damaging, requiring petroleum to produce, and it isn’t biodegradable, eventually ending up in landfills.

An E-Team from Rensselaer Polytechnic Institute is looking to change all that with an environmentally friendly, cradle- to-cradle insulating material they call Greensulate. The twist? Greensulate is made primarily from oyster mushrooms. Not exactly your typical approach to home insulation, but challenging the status quo and coming up with novel approaches is a trademark of the growing green building industry—and of innovators in general.

So how does it work? You start by combining perlite (a material used in potting soil), vermiculite (a mineral), water, starch, hydrogen peroxide, and mushroom cells. Pour the mixture into a panel mold, put it in a dark place, and wait. Over the course of one to two weeks, the mushroom cells digest the starch and form mycelium, tiny unicellular fibers similar to the roots of a tree. When the fibers intertwine, they form a rigid insulating material.1 Dry the panel to prevent fungal growth and voila: you’ve got a low-cost, organic composite board that requires no petroleum to produce and biodegrades at the end of its life cycle.

The idea to use mushrooms for insulating material came through a happy mix of personal experience and innovative coursework. Eben Bayer, co-founder of the team, was raised on a Vermont farm and learned gourmet mushroom harvesting from his father. Bayer put that knowledge to good use in school, hitting upon the idea for Greensulate while working on a sustainable housing assignment in Burt Swersey’s Inventor’s Studio course at RPI. Swersey urged him to develop the idea further, and Bayer soon brought in Gavin McIntyre, an RPI student with a keen interest in sustainable technology.

The two meshed, quickly winning Advanced E-Team funding, taking first place in the inaugural ASME I-Show competition, and winning the 21st Century Challenge Competition hosted by Oxford University’s Said Business School.

“Winning the E-Team and other funding was a critical step for us in building our business,” said Bayer. “It came at exactly the right time, as we were making the leap from an institutional research product to a growing company.”

The two graduated from RPI, but instead of taking jobs with other companies they incorporated as Ecovative Design ( to pursue the opportunity full-time. Why go the risky entrepreneurial route instead of taking more secure jobs?

“The excitement of doing something great for the world,” according to Bayer. “It was an intimidating choice at the time, but we’re both thrilled to have made it.”

For McIntyre, the final factor in deciding to start a company around the technology was the Advanced Invention to Venture program hosted by the NCIIA. “The knowledge that we gained from the workshop gave us such a strong footing to initiate the venture,” he said.

What’s on the docket for Ecovative now that they’re a real company? For one, they’re working on ASTM compliance certification for the insulating board, work that will be completed this summer and fall under a grant from the State of New York. Further research and development still needs to be done on the board itself, and the team estimates it won’t be commercially available for at least a year. They are, however, actively pursuing commercialization and manufacturing partners.

And Ecovative isn’t stopping at green insulating material. Bayer and McIntyre view Ecovative Design as a research firm dedicated to generating a suite of environmentally friendly products for a variety of markets. They made their first real sale recently: a plant pot for home gardens that rapidly breaks down once placed in the soil, acting as a fertilizer.

Next in the pipeline is Negative Volume, a green replacement for styrofoam packaging material. Negative Volume is produced using agricultural byproducts and is entirely compostable, so when you’re done unpacking that new computer, toss the peanuts in the garden. They make excellent fertilizer. It’s that kind of sustainable thinking that could very well guide Ecovative Design to great success.


1. From “Organic Insulation” by Susan Cosier,