UM students build sustainable straw-bale house at Campus Farm
A University of Michigan green building class plans to unveil a sustainably-built, straw-bale house located at the Campus Farm next Monday, May 29. Led by Joseph Trumpey, an assistant professor of art in the School of Art & Design and natural resources in the School for Environment and Sustainability, the team of about 20 students began construction on May 2 and has since spent six days a week at the build site, many of the students living in nearby tents. The straw-bale house will be the first official student-constructed building in Ann Arbor.
Last spring, Trumpey’s green building class built a straw-bale structure at the U-M biostation in Pellston, Mich. Though the two buildings are similar in design, the first is smaller, with a 20-by-20-feet interior and a different roof design. Some students, like Taubman junior Wendy Zhuo, worked on the project in Pellston and enrolled in Trumpey’s course again this year. Zhuo said she enjoyed being able to help with funding and grants this time, rather than doing purely hands-on work as she did last spring.
“It’s nice being on the back side of stuff and seeing more of the project instead of just starting the build,” Zhuo said.
The project is supported by about 20 donors. Most of the money for the straw-bale house initiative comes from University-affiliated sponsors, including the Planet Blue Student Innovation Fund and the Third Century Initiative. The remaining funds and materials come from other donors, like Turner Electric.
Trumpey hopes the new building will serve as a community gathering spot and a focal point for the Campus Farm, which has few other buildings on site. In the future, classes and meetings will take place in the straw-bale building, as will sustainability-focused events hosted by Michigan Dining, one of Trumpey’s partners.
According to Trumpey, the initiative is an exercise in sustainable agriculture. Trumpey values green living; in fact, both the Pellston and Ann Arbor straw-bale structures are smaller-scale versions of his own home: a solar-powered straw bale building that has housed Trumpey and his family for almost 10 years.
Like Trumpey’s home, the straw-bale house will be completely off the grid, relying fully on solar power generated by a 1.5-kilowatt array of roof panels attached to eight golf-cart batteries. Additionally, the house is built of sustainable materials, mostly straw and mud.
“Being able to use a lot of local, low-energy natural materials is really the heart of this,” Trumpey said, adding that he even collaborated with Campus Forestry to harvest wood for the structure’s scaffolding.
The structure is supported by wooden trusses and beams and sits on concrete posts extending below the frost line. The walls of the house rest upon a washed gravel trench. Trumpey used gravel rather than concrete for support because concrete has a high carbon footprint.
“One of the green building concepts is to try to minimize your concrete use because concrete has a lot of embodied energy in it,” Trumpey said. “It takes a lot of fossil fuels.”
Constructed of packed straw bales, the walls are covered in three layers of natural plaster. The first layer is clay, and the second two are different types of adobe, a mixture of clay, sand and chopped straw. Coating the exterior of the walls is lime putty, which adds strength and water resistance. The structure is also protected from weather by a wraparound porch.
Trumpey designed the Pellston and Ann Arbor straw-bale houses alongside Doug Farr, a U-M alum and head of the architecture firm Farr Associates. Farr, who attended the U-M biostation in 1977, specializes in sustainable urban design and has published two books on the subject. In an email interview, Farr wrote the new straw-bale building gives the community an idea of what the future of architecture might look like.
“The straw-bale building at the Botanical Garden will be what the book calls a Pilgrimage Site, an outlier demonstrating the viability of a preferred future,” Farr wrote. “Projects like this increase our collective optimism that we can tackle the big challenges at the pace we need to. We love the work we do.”
According to Art & Design senior Livvy Arau-McSweeney, who participated in both the Pellston and Ann Arbor builds, believes working on the straw-bale structures has inspired her to think more deeply about sustainable architecture.
“Since last year, I look at buildings – I look at spaces – super differently; I notice so many more things,” Arau-McSweeney said. “If I do end up on another construction project, I can think about what are more sustainable ways to go about it.”
Though he hasn’t scheduled another straw-bale project for next year, Trumpey hopes to keep engaging in green architecture initiatives; right now, he’s brainstorming sustainable dorm design. Overall, Trumpey said, he thinks the hands-on sustainable building experience has empowered his students. Arau-McSweeney said the projects have indeed been valuable, both in terms of skill-building and bonding with her peers.
“The skills we’re learning in this project, I don’t know if I would learn them anywhere else,” Arau-McSweeney said. “It’s also community building, that’s one of my favorite parts about it, is working with people. You’re living with them for 30 days, you’re doing this super intense thing, so it’s not only about the skill set, but it’s also about social interactions and getting to know people better.”