Developer Better Together 2030 is working with Alquist 3D, Hodge Construction, Axiom Consultants and Neumann Monson Architects on a 3D-printed build in Iowa City that the partners believe would be the first multistory, multiunit residential building printed in North America.
Construction is expected to start this summer, and the developer is in conversations with the city about a potential site. Better Together has submitted an application to the Housing Trust Fund of Johnson County's revolving loan program for funding support, said Cady Gerlach, Better Together 2030 executive director.
The $1.8 million project would include six units. The three-bedroom townhomes will be sold as affordable housing to residents who earn 60 to 80 percent of the area median income, Gerlach said.
City Manager Geoff Fruin said the project is "truly a community effort" with the local partners involved. He said the build would be a "quality, long-term asset" in the city.
HOW DOES IT WORK?
Mannheimer said a 3D-printed home is built much the same as a traditional build except the walls are made out of concrete. Instead of pouring the concrete in a form, it is extruded by a giant robot.
"That's really the only difference," Mannheimer said. "Eighty percent of the home is still built the exact same way as any other home. We still need your electricians, plumbers, roofers, HVAC folks, all those people to build out the home."
An architect still designs the home, and the design is turned into a computer file that communicates the instructions to the 3D printer. The print head layers the concrete material until the walls are built up. As the interior and exterior walls are built up, there is space between them to allow for electrical, plumbing and insulation.
Alquist 3D uses reinforced concrete for the walls, which is two to three times stronger than traditional concrete and sets faster.
Alquist 3D has printed four homes in Virginia, with three of those homes built in partnership with Habitat for Humanity. Alquist 3D's first home, printed in Williamsburg, Va., is the first 3D-printed, owner-occupied home in the country.
Alquist 3D also is working to print 10 homes in Muscatine.
The Iowa City build will use the reinforced concrete mix, but Mannheimer said the company also is experimenting with different materials — such as recycled glass and recycled plastic — to help make a more sustainable mix.
"The ultimate one that we want to make is a hempcrete," Mannheimer said. "Hemp is incredibly strong. This will be a much greener material to us."
Researchers at Texas A&M University received a $3.74 million grant from the U.S. Department of Energy to explore 3D-printed buildings using hempcrete for affordable and sustainable housing and construction. Hempcrete is made by mixing hemp powder and fibers with lime and water, according to the university.
COST SAVING GOALS
The current supply chain issues, labor shortages and rising construction costs all come into play when looking at the future of 3D printed homes. Mannheimer said the cost right now is typically on par or slightly lower than a traditional build.
"We're still very early into the industry," he said. "It's really a scale game. When we're printing multiple homes at a time, that's where we can achieve really high savings."
It's possible that real cost savings could be realized by the second or third project in Johnson County, Mannheimer said.
Mannheimer said the savings of 3D-printed homes come into play in three ways: materials are more readily available and cost less, less labor is needed and the project takes less time to complete.
For a one-story home of about 1,200 square feet, the exterior walls can be printed in 20 to 25 hours, Mannheimer said. This can shave off anywhere from one to four weeks from the traditional process of framing out a home, he added.
The goal, Mannheimer said, is to get close to 30 percent savings by the end of 2024.
INDUSTRY IS 'STILL VERY NEW'
With all the benefits and potential cost savings, why aren't there more 3D-printed homes? Mannheimer said the industry is still very new and needs to be adopted widely. He said there are fewer than a dozen 3D-printed homes in the country.
There are three major things that are "going to get 3D over the hump and really commercialize it," Mannheimer said.
"The robots need to get smaller and easier to transport, and that's already happening," Mannheimer said. "No. 2, the material needs to drop in cost — that is in process right now — and we're probably going to see less expensive materials here in the next six months. And then the big one is experience."
Alquist is launching a new program for groups that want to become a licensee or to lease printers through the company. The company also is debuting a 3D printing curriculum at Muscatine Community College this fall and students will help work on the homes being built in the area.
"We'd like to spread that to Johnson County as well and work with Kirkwood (Community College), as well as the Iowa City school district," Mannheimer said.
EMBRACING INNOVATION
Mannheimer said Iowa is well-positioned to grow as people are leaving big cities due to high cost or the expansion of remote work, as well as people moving because of climate change.
"But we can't bring people here if we don't have anywhere to live, and those places need to be affordable and attainable and well made," Mannheimer said.
Among the larger goals is "embracing innovation," he said.
"We want to show that Johnson County is trying to advance, and Iowa as a state is trying to advance, and we want creative entrepreneurs to come to our state and help grow our economy," Mannheimer said.
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