It looks more like a project at NASA than a home construction site.

Just outside Austin, Texas, massive machines are squeezing out 100 three- and four-bedroom homes, in the first major housing development to be 3D-printed on site.

One of the nation’s largest homebuilders, Lennar, is partnering with ICON, a 3D printing company, to develop the project. Lennar was an early investor in ICON, which has printed just about a dozen homes in Texas and in Mexico. These homes will go on the market in 2023, starting in the mid-$400,000 range.

“This is the first 100 homes, but we expect to be able to bring this to scale, and at scale we really bring cycle times down and we also bring cost down,” said Stuart Miller, executive chairman of Lennar.

ICON claims it can build the entire wall system of the home, which includes mechanical, electrical and plumbing, two to three times faster than a traditional home and at up to 30% of the cost.

“We exceed code requirements for all the different kinds of strength, wind, compressive strength by about 4x. We’re about two and a half times more energy efficient,” said Jason Ballard, co-founder and CEO of ICON.

The printers are designed to operate 24 hours a day, but they don’t because of area noise restrictions. They are almost fully automated, with just three workers at each home. One monitors the process on a laptop, and one checks the concrete mixture, which has to be adapted to the current weather conditions. Another works in support, misting the area with water or adding new material into the system.

“The promise of robotic construction is a promise of automation, reducing labor – therefore reducing labor costs,” Ballard said.

ICON aims to get the number of operators down to two over the next 12 months, Ballard added. Eventually, he wants even fewer operators. “I think the sort of Holy Grail is where one person can watch a dozen systems you need one person to watch a dozen systems,” Ballard said.

The way it works is a digital floor plan is loaded into the software system called Build OS, which then prepares it for robotic construction. It will automatically map out the structural reinforcement, placing the electrical and plumbing outlets during the print. The printers then squeeze out rows and rows of a proprietary concrete mixture that looks much like toothpaste, slowly building up the structure.

Other companies, like California-based Mighty Buildings, are also using 3D printing technology, but they print the homes in a factory and then move them on-site. ICON brings the factory to the site.

“With this project, we’re improving our total house count 400%, and we expect to like continue at least doubling for the next three to five years,” said Ballard. He said he already has plans to work with other large-scale builders. DR Horton is another of ICON’s early investors.

Lennar’s Miller said his primary focus is on bringing more affordable homes to the market, and he sees this as one way to do that. But he knows it’s also still the early stages.

“This is all about innovation. If you go around the country and speak to officials at the local and state level, the single biggest question is: How do we provide workforce housing, affordable housing,” he said.

Lennar began plans on the project with ICON when the housing market was still red-hot, driven by strong demand and record-low mortgage rates. Now mortgage rates are more than double what they were at the start of the year, and demand has fallen off sharply, suggesting their could be added risk to this project.

“We still focus on our core business, making the trains run on time, building homes across the country, and as the market cycles up and cycles down we adjust our business,” said Miller. “Innovation is a cycle as it sits on the side of our business because we know, looking forward, there’s a housing shortage out there.”