3D-printed houses poised to go mainstream

• At least one is also adapting its technology to mass-produce homes without releasing too much carbon into the atmosphere.

What's happening: A handful of companies are erecting new subdivisions featuring 3D-printed houses.

• Instead of conventional materials like steel, aluminum and lumber, 3D-printed structures are built by a robot squeezing a cement mixture out of a nozzle, layer upon layer, like a soft swirl ice cream cone.
• It's the same additive manufacturing process used to make everything from dental implants to airplane parts — just on a much, much larger scale.
• Only a few dozen 3D-printed homes have been built, or proposed, so far in the U.S., but that's about to change.

What they're saying: "After years of R&D, the market is nearing a tipping point as companies are moving beyond pilots and demonstration projects," according to market researchers at Guidehouse Industries.

• "Considering current tight construction margins and labor shortages, 3D printing has the potential to revolutionize construction," they wrote, adding that widespread adoption is still years away.

Where it stands: Among the early pioneers is Austin, Texas-based ICON, which has delivered more than two dozen 3D-printed homes in the U.S. and Mexico and just raised $207 million to expand.

• The company prints homes on-site, using its Vulcan construction system, with a gantry-mounted nozzle that lays down the house's walls, layer by layer.
• Its proprietary Lavacrete cement mix is "a closely guarded secret" that combines ordinary Portland cement with "advanced additives" for structural integrity.
• The homes are designed to be energy-efficient and withstand extreme weather and earthquakes, ICON says.

Mighty Buildings, a competitor, offers an alternative that focuses equally on the housing and climate crises.

• The San Francisco-based company aims to become carbon neutral by 2028 — more than two decades ahead of the rest of the construction industry.
• "We make houses as tools to fight climate change," co-founder Sam Ruben tells Axios.

How it works: Mighty Buildings uses 3D printing to produce modular panels in a factory, then delivers them to the lot for assembly.

• The panels are a synthetic stone made from a polymer composite and include a steel frame, insulation and even gypsum board, or drywall, for the interior walls.

• With robotic tools, the panels can be milled for the desired look, like stucco or siding.

Mighty Buildings started out printing "accessory dwelling units" — small guesthouses that are one answer to the housing shortage.

• It's now marketing 3D-printed home kits — similar to the Sears catalog's mail-order home kits in the early 20th century — for $349,000.
• It is also partnering with a developer, Palari Group, to build two subdivisions in California.
• Their 15-unit neighborhood in Rancho Mirage, near Palm Springs, will be "the first 3D-printed, net-zero-energy community," the companies say.
• With built-in solar panels and storage batteries on-site, homeowners won't spend a nickel on electricity, says Ruben.

Yes, but: Construction is a major contributor to climate change. It takes enormous amounts of energy to produce cement, a key ingredient in concrete, the ubiquitous foundation of our built world.

• The cement industry alone is responsible for 8% of global CO2 emissions, according to the World Wildlife Fund.
• That's one reason Mighty Buildings is partnering with a company that figured out how to trap those emissions in an innovative low-carbon cement.

The bottom line: It's too early to say whether 3D-printed houses will meet the test of time, says Henry D'Esposito, construction research lead at JLL, a real estate services firm.

• "We've never seen one of these at 20, 30, 40 years old," he tells Axios.