Constructing a house is a complicated endeavor. There’s a need for highly specialized materials, sometimes sourced from far away, along with skilled workers who can install, adjust ,and tweak everything to make a house a home.
The process is typically slow and expensive, and generates a huge amount of wasted material. The Oakland, CA-based market research firm Cleantech Group estimated that the construction industry will produce 2.2 billion tons of waste globally by 2025.
As a result, some home builders are now turning to three-dimensional (3D) printing methods to produce components, and even entire houses. To accomplish this, they are turning to new types of concrete, mortars, plastics, metals, and bio-based materials.
Also known as additive manufacturing, 3D printing can shrink a typical 18-month to 24-month construction process into just a few months, or even, in some cases, into days. 3D printing methods are also able to take advantage of sustainable materials, making the technology well-suited to the creation of future housing, including inexpensive structures for the homeless and people in developing nations.
“Prefabricated 3D printed homes reduce the amount of labor required to build a home, thereby making homes safer, potentially cheaper, and much faster from design to completion,” says Buff López, an analyst for Cleantech Group, a research firm that tracks sustainable innovation.
Building Better
The technology underlying 3D printing has evolved mightily over the last few years. Within the construction industry, systems can now use additive techniques for many parts of the construction process, including laying concrete, constructing walls, and producing components that go inside a structure, including windows, doors, and roofing.
In some cases, a home builder installs a 3D printing system around the perimeter of the space where the structure will go; a robotic device lays concrete and other materials within that space. It also is possible to install smaller 3D printing systems on the front of a tractor or within a structure, and use them to add metal, plastic, wood composite, or concrete to the structure, layer by layer.
“These systems often resemble a desktop 3D printer, but they scale to the size of the building,” says Tyler Ley, Regents Professor in the School of Civil and Environmental Engineering at Oklahoma State University. “Some use robotic arms to reach specific parts of a house.”
Also emerging are companies that use 3D printing to produce components offsite. For example, California-based Mighty Buildings Inc. offers design ready drawing sets, as well as architectural services that support 3D printed structures. Its printing technology produces steel frames, composite stone panels, and foam insulation that are manufactured offsite and installed at a construction site. So far, the company has produced 60 houses worldwide.
Mighty Buildings has developed a system that produces a fast-curing material called LUMUS, which the company says is five times stronger than concrete and 30% lighter. In addition, LUMUS is soundproof, self-extinguishing, resistant to mold, mildew, and insects, and is certified to be earthquake-resilient. What’s more, the company boasts it can incorporate 60% recycled materials and reduce waste by 99%.
“The U.S. is short 650,000 construction workers, as homebuilding continues to operate with antiquated processes and little to zero productivity growth,” says Chris Murphy, chief strategy officer for Mighty Buildings. “With 3D printing, we’re witnessing an expansion in aesthetic possibilities, decreased times to build, more resilient buildings, and dramatic reductions of onsite waste.”
Another company, Austin, TX-based ICON Homes, has completed the 3D-printing of more than 130 houses across the U.S. and Mexico, including developments in Marfa and Georgetown, TX. Its 3D print head, which resembles a highly flexible giant articulated robotic arm, can take on different forms and bend in different ways, depending on the specific need. It lays down a low-carbon material called CarbonX, which is a novel type of concrete sourced from local materials.
The result is a system that can print quickly onsite without the need to conform to conventional design patterns, such as geometric and squared off rooms. In addition, 3D printing methods can incorporate smart systems, such as lighting controllers, video doorbells, and thermostats. At the most basic level, such as a one-room house, the price can be as low as $15,000.
Drawing on Progress
The idea of building 3D printed houses is gaining momentum, albeit slowly. “We don’t have enough skilled tradespeople, and 3D printing can help fill the gap while delivering on more economical and rapid construction methods,” Ley says. López echoes this thinking: “These robots don’t take jobs away from people. They’re helping people perform better at jobs they’re already doing.”
Although the industry is rapidly conquering technical barriers, cultural obstacles remain. This includes the fact that the technology is still relatively new, and shifting to 3D printing from more-standard building methods introduces perceived risks for home builders. “The technology is still evolving. There are still some issues that need to be addressed, particularly in regard to materials and simplifying techniques,” Ley says.
For now, cost is also a factor. While printing a basic one-room house is inexpensive, building a typical house that way is a different story, since it typically costs about $25,000 to $30,000 to add each additional room. Consequently, “It’s still mostly a luxury purchase,” López says. However, as prices for equipment and materials decline, the technology could slash construction costs. Murphy estimates that, when adopted at scale and combined with additional energy efficiency measures, 3D printed houses could lower total cost of home ownership by up to 35%.
Consequently, 3D printed housing could be ideal for housing the homeless, and serve as a path to progress in developing nations. Already, Ley and his students have developed a 3D printer that mounts on the front of a tractor and uses a vertical system to print from the side. “If you can rent a tractor, you can print a house,” he says. So far, the group has “printed” two buildings. Completing a single basic structure took four people (two college students and two high school students, none of whom had any previous construction experience) a total of 14 hours, Ley says.
Ley now hopes to print more buildings, and potentially to commercialize the 3D printing system, which could also be used to produce retaining walls, water collection tubs, and other critical infrastructure. “People need to see that the technology can work and that there’s no risk before it can be widely accepted,” he says. “3D printing has the potential to be very disruptive, but it’s going to take time to gain widespread cultural acceptance and attractive price points.”
Samuel Greengard is an author and journalist based in West Linn, OR, USA.
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