UM Professor Glenn Wilcox on Building with Hemp & Fungi

University of Michigan Professor Glenn Wilcox Brings Cutting-Edge Bio-Based Materials Research to iHemp Michigan’s Hemp Building Workshop Series

The future of sustainable building and design may be growing in a lab in Ann Arbor. Glenn Wilcox, Associate Professor of Architecture at the University of Michigan’s Taubman College, joined the iHemp Hour to discuss his groundbreaking work with mycelium and hempcrete—two bio-based materials that could transform how we think about everything from furniture to insulation.

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Wilcox, an educator, designer, and maker whose award-winning work spans furniture design to boat fabrication, has spent years exploring the intersection of traditional craftsmanship and cutting-edge technology. His current focus? Creating furniture and building materials that are not just sustainable, but completely compostable.

A Sailing Trip That Changed Everything

Wilcox’s journey into bio-based materials began with an eye-opening experience. In 2017, he and his wife Annika took a 14-month sabbatical, sailing from Newfoundland to the Caribbean and back with their daughter.

“One of the things that was striking in that trip was seeing all of the results of climate change all along that Coast—the higher tides, the floods, places that were completely flooded, the strength of the storms. When we came back, I made a pledge to myself that I would look for ways to use materials that were much more sustainable, much more bio-based.”

The 2018 Farm Bill, which legalized industrial hemp cultivation, provided the perfect opportunity. Wilcox immediately began sourcing hemp hurd (the woody inner core of the hemp stalk) from North Carolina—one of the few states producing it at the time—and started experimenting.

150 Experiments and Counting: The Hempcrete Journey

What followed was an intensive period of material exploration. Wilcox created approximately 150 small test studies of hempcrete, experimenting with different binders and compositions to understand the material’s properties.

Hempcrete (also called hemp-lime) is a biocomposite made from hemp hurd mixed with lime and water. It offers excellent thermal properties, fire resistance, and moisture regulation—making it ideal for building applications.

Wilcox’s experiments revealed important insights about hempcrete binders:

• Hydraulic lime from France (where hemp construction never stopped) contains natural pozzolans and produces excellent results
• Metakaite (a clay-based addite) works well when mixed with lime at approximately 50/50 ratios
• Slag and fly ash can replace cement for more sustainable formulations
• Agricultural lime from tractor supply stores has also shown promising results

“That’s something I want to go back to… I’m interested to hear what different mixes that people are using to get good binding results.”

Enter the “Third Kingdom”: Mycelium-Based Composites

While hempcrete works beautifully at wall scale, Wilcox discovered it was too brittle for small-scale furniture applications. That’s when a student introduced him to mycelium—and everything changed.

Mycelium is the vegetative body of fungi—essentially the “roots” of mushrooms. It’s made up of incredibly dense networks of single-celled strands called hyphae. To put this in perspective: in a handful of old-growth forest soil, you’d find approximately 26 miles of hyphae.

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“Fungi is not a plant—it’s actually what they call the ‘third kingdom.’ Mycelium exists mostly underground, and then you’ll get mushrooms sprouting up. It’s a bit like the relationship between a tree and an apple, where the apple is equivalent to the mushroom and the tree is the mycelium.”

How Mycelium Works as a Building Material

The magic of mycelium lies in its binding properties. When grown through a substrate like hemp hurd, mycelium acts as a natural adhesive, creating a material with similar properties to EPS (expanded polystyrene) foam—but completely biodegradable.

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Ecovative, a pioneering company founded in 2009 by two Rhode Island School of Design students, has grown into a $60 million company producing mycelium-based materials. Their applications include:

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• Packaging – Compostable alternatives to styrofoam
• Building insulation – Similar R-value properties to hempcrete
• Faux leather – When grown without a substrate
• Sheet products – Heat-pressed materials resembling OSB

“They just built a tiny house that used the mycelium as the insulation because it has very similar properties as hempcrete does in terms of its R-value… and it really binds and sticks to stuff really well.”

Growing Furniture: The Process

Wilcox has been working to reverse-engineer mycelium production for furniture applications. His process involves:

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1. Sterilization – Substrates must be autoclaved or pasteurized (soaking in lime water at 11-12 pH works for oyster mushrooms)
2. Inoculation – Adding mycelium spawn to the substrate
3. Growing – 5 days in a mold wrapped in plastic
4. Drying/Heating – Kills the mycelium and hardens the material
5. Finishing – Sealing with wax or bioplastics for protection

A key insight from Wilcox’s work: mycelium should be thought of as “upholstery” rather than wood. His successful furniture pieces use internal cores (like cardboard sonotubes) for structure, with mycelium growing around them as a bonded exterior layer.

“The first time I made something out of mycelium, it was a mistake the way I thought of it. I always thought of it as a kind of wood, and it’s not—it’s sort of more like a kind of upholstery. You really have to think of it like EPS foam.”

The Ultimate Goal: Completely Compostable Furniture

Wilcox’s vision extends beyond simply using sustainable materials:

“My theoretical goal is to make a piece of furniture that’s completely compostable—that you could just throw it in the compost when it’s done, or it’s not going to poison the ground. It could actually maybe even add nutrients to the soil.”

Achieving this requires eliminating formaldehyde, metal fittings, and synthetic adhesives—a challenging but increasingly achievable goal as bio-based alternatives improve.

Student Demand Is Overwhelming

The next generation of designers is hungry for this knowledge. Wilcox recently proposed a course called “Biomaterials for Designers” for Fall 2023:

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“The response from the students has been overwhelming. The course filled up in about 10 minutes, and I just keep getting emails from students that want to take it… They’re very interested in these technologies and these materials.”

This enthusiasm signals a generational shift toward sustainable design practices—one that hemp is perfectly positioned to support.

Industry News Roundup

📍 Hash Bash Weekend in Ann Arbor

Mike Brennan reported on the upcoming Hash Bash festivities, warning attendees to arrive early due to the overlap with Michigan’s spring football game—an expected crowd of nearly 100,000 people. The Monroe Street Fair runs alongside the main event with food trucks, vendors, and samples.

Tip for attendees: Sons and Daughters United is offering a $40 tax-deductible donation deal that includes a map to 10-12 dispensaries offering approximately $200 worth of free products, with proceeds supporting cannabis conviction expungement efforts.

🏛️ Lansing Under Investigation

A federal bribery investigation is targeting former House Speaker Rick Johnson and lobbyist Steve Linder related to the medical marijuana licensing era. While charges haven’t been filed yet, the investigation raises serious questions about licensing practices.

🌾 Texas Approves Hemp Feed for Livestock

In a significant win for the industry, Texas has joined Montana in approving hemp seed-derived feed for horses and poultry. iHemp Michigan continues advocating for similar legislation in Michigan. The American Feed Association and the US Hemp Feed Coalition are making progress on federal approval, with laying hen feed receiving tentative approval.

Upcoming Events

📅 The Why and How of Building with Hemp Workshop

Date: April 15th Location: Taubman College of Architecture and Urban Planning, University of Michigan North Campus (Room 1360) Address: Enter from Fuller Road; parking in rear lot across from VA Hospital Cost: $40 general admission | $25 students (includes lunch) Register: iHempMichigan.com

Glenn Wilcox will present his research and bring physical samples of his mycelium and hempcrete work. This is a rare opportunity to see cutting-edge bio-based materials up close and learn from one of the leading researchers in the field.

📅 Kim Croes’ Hempcrete Workshop at Fiber Fort

Date: This Saturday (limited spots remaining!) Location: Detroit Info: FiberFort.com or contact through iHemp Michigan

Kim Croes of Fiber Fort has openings in both morning and afternoon sessions. Kim is working on multiple hemp building projects this summer and offers hands-on experience with hemp-lime construction.

Recipe of the Week: Roasted Sweet Potatoes with Apricots and Curried Hemp Seed

From The Hemp Nut Cookbook

Servings: 4-6 | Time: ~1 hour

Ingredients:

• Sweet potatoes
• Apricots
• Hemp seed oil
• Zest of 2 lemons
• Sea salt
• Curry powder
• Shelled hemp seeds
• Fresh parsley, minced

Find the full recipe and over 100 more hemp recipes at iHempMichigan.com/recipes.

Need hemp hearts or hemp seed oil? Visit DownOnTheFarm.biz

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