On average it took more than 10 months to build a house in the United States in 2023, nearly three months longer than in 2015, according to government data. Economists and other experts blame the homebuilding sector’s poor productivity on culprits including stringent regulations and a shortage of skilled labor.

But they also cite another factor sometimes overlooked: The sector’s slow adoption of new innovations, which even the National Association of Home Builders (NAHB)acknowledges has been holding the industry back.

Now a group of startups and homebuilders are trying to rewrite this narrative by harnessing three-dimensional concrete printing (3DCP), a technology advocates say could revolutionize home building. Picture giant robots and automation techniques producing homes faster, cheaper and more safely than conventional methods. University research studies suggest concrete printed homes are stronger, have higher energy efficiency ratings and provide better resistance to fire, floods and high winds than conventionally built houses. Using precisely measured concrete material to print walls also can yield a smaller environmental footprint because there is little waste and no need for formworks that end up in landfills.

“We can’t keep doing the same thing we’ve been doing for the last 50 years and expect different results,” said Tim Stark, the owner of BeSpoke of Montana, a building and remodeling company in Billings. He is morphing his company to exclusively build concrete-printed homes.

Three-dimensional printing technology has long moved beyond hobbyists’ desktops to factory floors, where it’s now used to make everything from car parts to prosthetic limbs. The late Harvard business professor Clayton Christenson, who coined the term “disruptive technology,” considered 3D printing a classic disruptor because it is simpler, cheaper and more convenient than traditional manufacturing technology. In a 2024 report entitled, “Delivering on Construction Productivity is No Longer Optional,” the consulting firm McKinsey & Co. said 3D printing could help the sector “climb out of its productivity rut.”

The concept of giant automated house-building machines has become so irresistible that almost any 3DCP project is guaranteed to attract widespread attention. Consider the crowds that flocked to witness Florida’s first 3D-printed house. So many people wanted to see it the builder set up an online reservation system to manage tours. “We had schools visiting and professors coming from all around,” said James Light, the homebuilder who hired a 3DCP company to print the walls. “It was just kind of a spectacle, honestly.”

To try to untangle hype from reality, we spent three months gathering information from researchers, homebuilders, developers and technology companies to learn about 3DCP and understand the potential and challenges. We called and emailed companies that announced 3DCP projects in recent years to find out if they were indeed completed and if there was evidence printing was quicker or saved money than conventional builds.

Below we provide our account, but if you want the bottom line: Contrary to what’s been reported, the technology is not always faster or less expensive than traditional construction. Even so, it’s probably unwise to write it off. Most any supposed disruptive technology must run a marathon and 3DCP has only just left the starting gate.

First, some history

The technology may seem new, but 3D concrete printing goes back about 85 years, said Chaofeng Wang, an assistant professor in the University of Florida’s School of Construction Management, who studies the technology. Printing with concrete started in late 1930s when William Urschel, an Indiana investor and contractor, created a machine that extruded layers of concrete to build walls.

But nothing much happened until the mid-1990s when an engineering professor at the University of Southern California invented the earliest version of today’s computer-based robotic system to “print” concrete following a digital design. Behrokh Khoshnevis said the idea came to him when he was repairing cracks in the wall of his living room after the 1994 Northridge, California earthquake. A few years later he gained widespread attention for printing a 500-square-foot structure inside a lab, and he gave a TEDx talk and interviews in which he predicted the technology would transform the way we build houses at a fraction of the cost.

All these years later it seems the number of news stories and press releases vastly exceed the number of 3D printed buildings. In a paper recently published in the journal Buildings, researchers from Germany’s Technical University of Braunschweig identified 356 3D printed buildings constructed worldwide since 2013. Nearly half were built in 2024 (Figure 1), suggesting 3DCP may be gaining traction. But it’s hardly a drop in the ocean when you consider 948,000 single-family homes were built in the United States in 2024, according to the Census Bureau.

WorldwideSource: A Global Snapshot of 3D-Printed Buildings

Most 3D-printed buildings built so far are residences, but others include offices, storage facilities and exhibits. The majority have been built in the United States, followed by China, Europe and the Middle East, such as Dubai, which aims to become a global leader with a goal of using 3DCP for one-quarter of all new buildings in 2030.

According to various research studies and industry claims, 3DCP may save roughly 20% to 30% on the cost of building a house. Advocates say 3DCP allows as few as two or three workers to erect the walls, including one to use a handheld computer to ensure printing goes according to plan and another to manage concrete mixing and delivery. That’s far fewer than the array of workers — typically hard-to-find subcontractors — that builders rely on to frame a conventional stick-built house. But reported savings are difficult to quantify without real cost data, which is closely guarded and not readily available. Certainly, such estimates raise questions when you consider the cost of framing a house with interior and exterior walls, dry wall and other elements that 3DCP would replace make up roughly 20% of the cost of a new house, according to our review of NAHB data. Most costs are for foundations, roofs, doors, windows, and electrical and plumbing systems that are added the traditional way by construction workers. Austin-based startup Icon, which built the first U.S. permitted 3D-printed home in 2018 for reportedly $10,000, seems to have begun tamping down expectations of huge cost savings. The company announced last year it is taking orders for projects starting at $25 per square foot for wall systems, which it said was lower than the cost of conventional wall systems based on data from the NAHB. Icon claimed this would represent a savings of up to $25,000 for the average American home.

Local and state building codes can also pose a hurdle. Unlike traditional wood-frame and cement-block construction, which are well-defined in local building codes, printing concrete walls is considered an “alternative means and methods” in the International Building Code, and many states and local jurisdictions are slow to approve 3DCP projects. “The key challenges to adopting 3D-printing broadly are scaling the technology to meet demand and securing municipal approval to use the technologies in various jurisdictions,” said Brad Conlon, senior vice president of development for D.R. Horton, the largest U.S. homebuilder.

In the 3DCP market, Icon and Apis Cor are among hundreds of companies trying to hone operations and win business. They have many different approaches. While Icon and Apis Cor don’t sell their pricey machines — they serve as printer contractors — other manufacturers sell theirs and train builders to assemble and operate them. Some homebuilders are testing the waters by adding the technology to their box of tools, while others are brave enough to put all their chips in to focus only on 3DCP.

Many projects are aimed at addressing affordable housing issues, though it’s hard to see much cost savings so far. On Dec. 6, 2024, about 150 news reporters and community and elected officials flocked to a site in Melbourne, Fla., to watch a robot begin printing a 1,300-square-foot home for Space Coast Habitat for Humanity, with funding from Wells Fargo Bank and the city of Melbourne. When we followed up in February, the printing was weeks behind schedule, said Anna Terry, executive director of the affordable-home building organization. The house is being built on land it already owned, will cost roughly $250,000, about the same as a similar home built with conventional methods, she acknowledged. Terry was optimistic the job would be completed soon after the robotic printer was relocated to its fourth and final printing position. “When you’re pioneering something it’s not as quick as you think,” she said.

The most notable recent project we learned of is Zuri Gardens in south Houston, which would be the nation’s second-largest 3D-printed neighborhood, with 80 homes priced in the $200,000s. It is being developed by Cole Klein Builders of Houston with houses printed by Hive3D. The partners’ proposal to use 3DCP was selected recently by the city of Houston through a competitive bidding process. The city is kicking in $1.8 million in affordable housing funds. “Otherwise, we couldn’t do it,” said Harry Klein, cofounder of Cole Klein Builders. Construction was slated to begin in 60 to 90 days.

As Christensen explains in his book, “The Innovator’s Dilemma,” disruptive technology may often have early performance problems or may not immediately have a proven practical application. It may take several iterations before the technology works out problems and its rate of improvement exceeds existing technology. Brian Potter, a structural engineer who follows the 3D-printing construction industry, wrote on Substack: “The important thing for building 3D printing isn’t the current state” but where it is on the curve of a classic disruptive innovation. “Unfortunately, figuring this out is difficult.”

By this yardstick, we won’t know for a while whether 3DCP will make us wildly more efficient homebuilders. Check back in a few years. It has just entered the race.