Illustration of a house made of Styrofoam.

Illustration by Tabitha Walters

Al Gallup is ninety-eight and has lived in Ann Arbor all his life. However, the retired school administrator has never seen anything like the building now under construction near his home on Bydding Rd. “They’re building a house with a method I’ve never seen—Styrofoam—a lot of concrete work, [and] now more Styrofoam blocks came in,” says Gallup.

The blocks “are insulated concrete forms [ICFs], hollow recycled Styrofoam blocks stacked and interlocked to create walls, then filled with concrete,” explains Peter Woolf, owner of the building. A retired U-M professor of chemical and biomedical engineering, Woolf bought the property in 2020 for $285,000 and demolished the existing house. Two years later, he acquired the house next door on Miner for $385,300; during construction, he’s using it as an office and storage facility.

The new building, which Woolf calls Winter Garden, will be a very unusual Airbnb—one with net-zero energy consumption. He’s using fiberglass rebar, rather than traditional steel, in the ICFs to further increase efficiency, and a greenhouse and pond on the roof will feed rainwater to a 60,000-gallon cistern below—he describes it as an enormous thermal battery with an energy storage capacity equal to 120 Tesla Powerwalls. A wood-burning stove will heat a sauna on the side of the house, with the collected heat returned to the cistern. Electricity will come from an eighteen-kilowatt grid-connected solar array on the roof with a backup battery.

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Woolf plans to live in a lower-level apartment next to the cistern, leaving three ensuite bedrooms upstairs to rent out. He says he chose Meadowlark Builders for the project because they were undaunted by the project’s complexity.

“We grew as a company taking on alternative construction methods, including ICFs,” says Meadowlark cofounder Doug Selby. Woolf says that he had optimistically estimated an eighteen-month timeline, but is now telling everyone to add another eighteen months. “You can have it done quickly, cheaply, or well. You can choose two, but not all three, right?” he says. “I opted for well and cheap rather than quick.”

When Winter Garden is finished, Woolf will turn his attention to the house on Miner, which he calls Sun Haven. There, he envisions “a sustainable retro-build look … to get to something on the order of passive house [energy] standards. …

“My mission is to be the steward and docent of the space and share it with the community. If I hide it under my hat, it won’t benefit anyone but me.”