Is 3D printing the future of home construction?

3D printing, considered cutting-edge technology a decade ago, is moving well beyond desktop units printing plastic parts in limited quantities. Case in point: Iowa-based research into the feasibility of 3D-printed houses – coupled with an Iowa City company already working in the field – that could serve as a foundation to revolutionize the traditional home construction process, leading to a faster and more cost-effective solution to affordable housing shortages.

Alquist 3D, based in Iowa City, has been working in the 3D home printing industry for the past four years, partnering with printer manufacturers COBOD, based in Copenhagen, Denmark, and Black Buffalo 3D, based in East Stroudsburg, Virginia, on the research and deployment of 3D home printing technology. To date, the company has worked with Habitat for Humanity chapters to build four 3D-printed homes in Virginia, with dozens more in the planning stages. And the Iowa State University College of Design’s 3D Affordable Innovative Technologies Housing Project is working with grant funding from several sources to meet the growing demand for quicker, cheaper solutions to affordable housing needs through 3D-printed homes. However, both groups agree, there’s much to be learned before 3D printing becomes the predominant standard for home construction, both statewide and globally.

ISU researchers studying pros, cons

Pete Evans, an assistant professor of industrial design at Iowa State University, has been working with Julie Robison, program manager for the Institute for Design Research and Outreach and community and economic development specialist for ISU Extension and Outreach, and Kevin Kane, associate dean for research and outreach in the College of Design, over the past two years on research into the nuts and bolts of 3D home printing. Thus far, the project has been awarded four grants. The first, a $1.4 million Strategic Infrastructure Program (SIP) from the Iowa Economic Development Authority (IEDA), is “trying to capture the advanced technologies that are involved in this type of work, to really pull the curtain off of this and and try to put together a comprehensive ecosystem around this type of technology,” Mr. Evans said, noting that 3D home printing has “the potential to change how we might produce affordable housing.” Other grants include funding from the American Recovery and Reinvestment Act to “try to understand the process from the human side”; a Community Development Block Grant for planning the educational and training component as part of a project to launch a 3D printing technical training program at Iowa Central Community College, including a certificate program launching this fall and a full associate’s degree program in the future; and a research grant to cover aspects of site design, community planning and research. Once fully funded, the project is proposed to total $2.14 million. The SIP grant will fund equipment and materials, including a 3D construction printer, printing materials and components, on-site robotics, mobile CNC machining, web technologies, and virtual and extended reality systems. The ISU team is also working with Brunow Contracting of Council Bluffs on a demonstration build that will produce 40 houses in Hamburg, Iowa, as part of that southwest Iowa community’s recovery efforts from 2019 flooding. The build will help the team to understand design, affordability, zoning and building codes, community engagement, and training as the project moves forward. Long-term, the ISU project is expected to encompass about 300 units in 20 different projects, mostly in southwest Iowa, Mr. Evans said. A small 3D printer has been installed at Iowa State for research purposes, and a larger unit capable of printing a full 3D home will be installed for the technical training program at Iowa Central. Test-printing of a six- to seven-foot tall wall section is expected to commence within the next month, and pending land acquisition and permitting, it’s hoped the Hamburg home project can launch sometime this summer. Currently, only the walls of a home can be constructed via 3D printing. Other facets of home construction, from roofing and drywall to plumbing, electrical, HVAC and other building processes, will still be completed by conventional contractors.

To construct a home, the 3D printer uses a giant robotic arm to pour a cement-like substance to make the walls. The framing of the house is extruded from the printer layer by layer from the ground up. Under ideal conditions, the walls of a home can be printed in as little as 18 to 25 hours. The material used is a combination of substances, which can include water, cement, aggregate, fibers and other materials, depending on what’s available at a construction site and the climate conditions under which the printing will take place. “One of the goals of the project is to ensure the material is immediate and adjacent to the site, to keep costs down,” Mr. Evans said, “so that it can be produced where the projects are being constructed, similar to any kind of mixing plant where you might be able to just have local concrete and a mixing truck to take concrete to a site.” Mr. Evans compared the material to a type of mortar. “We're definitely looking at trying to introduce different kinds of aggregate, perhaps up to about three eighths of an inch, which we're not doing today,” Mr. Evans said. “Our goal as we move this forward is to get more of a concrete-like definition, which means that it might be able to qualify for more existing building codes. We don't want to have mortar-built houses. We want to have something that is substantial, safe and healthy.”

Iowa City company already printing homes

Based in Iowa City, Alquist 3D has been working with 3D home printing technology for several years, with prints already completed on several Habitat for Humanity home projects in Virginia. Two of the homes are already occupied, and two others are currently being built out and will be occupied in April. Alquist 3D CEO Zach Mannheimer said his company began working in Virginia through a partnership with Virginia Tech University, formed during a conference hosted by the Department of Housing and Urban Development’s Virginia office. “We were on a panel with people from Virginia Tech, before anybody was really doing 3D homes in America, and we ended up applying for a grant together from the state of Virginia, which we received to print the first home,” he said. “That's how we got started there. We will still be printing in Virginia, this year and beyond. But we’re now putting a focus on Iowa.” The company will partner with local housing organizations, nonprofits, and Muscatine Community College to 3D print 10 homes in Muscatine in 2023, the company’s first endeavor in Iowa.

Mr. Mannheimer said the Muscatine Community Foundation is spearheading the project. “They've brought us in as the 3D printing group,” Mr. Mannheimer said. “Hagerty Earthworks of Muscatine is the general contractor, and we're collaborating on those 10 homes. So we begin with four of them in April, and then we'll do the last six in the fall.” Alquist is also developing a program to teach 3D printing techniques at Muscatine Community College, beginning this fall – the first 3D concrete printing curriculum in America. The 3D printer for the Muscatine project is a large robot-arm printer, currently being built by RIC Technology in Los Angeles. Previously, Alquist has used gantry-style printers for their Virginia home printing projects. Mr. Mannheimer said Alquist is one of several companies advising Iowa State’s research, but he termed Alquist’s work a “commercial venture,” while ISU’s project is an “academic pursuit.” “We’re going to be sharing our data with them, to help inform the process,” he said. “We’re several years ahead of where they are now.” Mr. Mannheimer said several other projects are in development, including projects in Iowa City. “We've got a couple groups in Cedar Rapids we're talking to,” he added, “and then we do have a couple of projects on the western side of the state. We probably have 30 to 40 different conversations happening right now with different communities statewide.”

Opportunities, advantages and challenges

Advocates of 3D printed houses tout several advantages – lower construction costs, faster build times, resilience to the elements, and training opportunities for a highly-skilled workforce capable of setting up, calibrating and operating the printers on site. Yet critics point to several factors as well. The printers are large and difficult to transport, making it difficult to transport them to rural and underserved areas – the very areas that face the most substantial affordable housing challenges. They also consume substantial amounts of electricity, and materials that are readily available in one area may be impossible to maintain in another, requiring flexibility in composition, temperature tolerances and structural rigidity. Mr. Mannheimer said he knows several challenges remain, but the advantages of 3D home printing provide a revolutionary road map for the future of structural engineering. “We believe that by using this technology, we're going to be able to drop the cost of housing 20% to 30% versus traditional construction,” he said. “That's not achievable today, but it should be achievable by the end of next year. Right now, it's really on par with traditional (construction). However, that's when you're just doing one home. When we're doing these at scale and printing several at a time, that's when we're going to realize significant cost savings. That's the work we're going to be doing this spring. “But on top of that, these homes are much stronger than traditional homes, so they're going to survive tornadoes, derechos, things like that,” he added. “They don't burn, and they're highly energy efficient. They’ll cut your energy bill by 50%. On top of that, you can do any type of design. You can make the walls look like anything that you want. They can look like brick, they can look like siding, you can do different shapes and sizes. It's virtually unlimited in terms of customization.” Mr. Mannheimer said he’s also gained experience in complying with local building codes and material standards. “We’ve already been able to overcome those challenges in Virginia,” he said. “I was at a permitting meeting in Muscatine, and surprisingly, the permitting and code concerns have not been issues, as we and everyone else thought they would be. At the end of the day, this is a type of concrete. The only difference between the concrete we're using and traditional concrete which has been used for hundreds of years to build thousands of buildings all over the world is that our concrete is stronger.” The technology behind 3D home printing is not new, Mr. Evans pointed out. The first 3D home was printed in China in 2015, and the first permit for a 3D printed home in the U.S. was issued in Florida about a year and a half ago, followed by the nation’s first owner-occupied homes in Virginia. “And there are other research studies that were done even before that,” he said, “but now, every month or so it feels like there's a first happening.” “What we're trying to do is model what  we see as best practices and then evaluate that against everything we can through conventional modes,” he added. “Understanding the materials, the cost, the timing, the labor – all of those pieces that are critical. If we are at a moment in time where we might be able to change the approach to housing – and I think we are there – how can we advance affordable housing in a time where it is incredibly needed? We've been doing this the same way for roughly the past 100 years. We need to look at the entire process of how we design and build our projects with a little bit more sophistication. And if we can do that, we will rapidly improve the process, saving money, labor, and materials.” Mr. Mannheimer said he feels the potential of 3D home printing is only beginning to be realized. “People are excited about it, but obviously skeptical,” he said. “They want to see more of it in practice, and we're out to help commercialize the industry. It's happening very quickly, and it's solving two major issues. One, we can help solve the housing crisis, which exists everywhere. And two, this is a workforce development process that will create many jobs in this brand-new industry. We really see this as a gateway to getting young people back excited about the trades.”