Japan’s construction industry is facing a productivity crisis, as soaring material costs and an aging workforce threaten the future of the nation’s $625 billion sector.
But an earthquake-proof 3D-printed house is giving hope that additive manufacturing could be the answer.
Unveiled in February, “Stealth House” is Japan’s first 3D-printed two-story home. Building-tech startup Kizuki collaborated with more than 20 companies, including ONOCOM to create the home, which meets strict building codes for seismic design in a country where earthquakes are common.
“It marked the first time in Japan that a full process — from feeding design data directly to the printer, to continuous on-site construction, and finally finishing works — was successfully realized at a two-story residential scale,” Rika Igarashi, Kizuki CEO, told CNN in an email.
Inspired by natural cave formations, the 6-meter (20-feet) tall, 50-square-meter (538-square-foot) house took just 14 days to print on site — from foundation to rooftop parapet — using a giant gantry printer, says Igarashi. The exterior walls employed a “hollow structure” filled with a reinforced concrete frame to meet building codes.
3D-printed construction (3DPC) technology has long been heralded for its ability to save time, reduce labor, increase safety at work sites, and substantially cut material waste, while enabling more flexible and unusual designs.
But governments and institutions have been cautious around new construction innovations, and slow to update regulations, creating a barrier to adoption.
Kizuki’s “Stealth House” is more than a demonstration, though: the home, in Kurihara City, Miyagi Prefecture, sold (for an undisclosed price), which the company says is proof that there is demand.
Japan’s falling birthrates and aging workforce have seen its productive population decline: in the construction sector, according to some calculations, 1.5 million skilled workers (45% of the total) are expected to retire within the next decade.
Daisuke Katano, a managing partner at Japanese construction consultancy firm YCP, says that 3D printing can combine “up to seven traditional on-site trades.” This can streamline coordination and bolster Japan’s productivity in residential construction — which is less than half the US level and has barely improved in decades, says Katano: “Recovering even five to 10 of those (percentage) points would be worth trillions of yen (billions of dollars) in unlocked output capacity.”
Currently, civil infrastructure — such as the world’s first 3D-printed train station, or a 273-meter (896-foot) road — accounts for around 62% of 3DPC applications in Japan.
But other markets, like entry-level and disaster-recovery housing, are growing: Katano points to Japanese construction startup Serendix’s 3D-printed budget bungalows, which were deployed to provide quick and affordable housing in the aftermath of a 7.5 magnitude quake in Noto Peninsula in 2024.
Kizuki is also looking at opportunities to supply housing in depopulated and remote regions, which it presented to representatives from seven municipalities at the SusHi Tech conference in Tokyo last week, one of Asia’s largest global innovation events.
“Even in areas with severe shortages of skilled workers, 3DCP makes it possible for a small team of operators to construct high-quality buildings,” says Igarashi. “In that sense, the technology has the potential to directly address regional disparities in housing supply.”
Despite the high upfront costs for 3DPC equipment, Igarashi says the main challenges to adoption are “increasingly institutional rather than technological.”
“From a regulatory perspective, compliance is currently confirmed through individual building approval applications on a case-by-case basis,” she says. “For wider adoption and greater efficiency, dedicated technical standards and regulatory frameworks built around 3DCP methods will be necessary.”
Tetsuya Ishida, a civil engineering professor at the University of Tokyo, agrees: standardized evaluation methods — such as technical guidelines recently developed by the Japan Society of Civil Engineers — need to be adopted to reduce bureaucracy.
“While regulators have historically been cautious, the tide is changing significantly,” says Ishida. He highlights the inclusion of 3D printing in the government’s “New Technology Introduction Promotion Plan,” as well as the precedent set by “Stealth House” as key steps to make future approval processes “dramatically smoother.”
While Katano at YCP agrees that “Stealth House” helps to give 3D-printed homes more credibility, “the risks relative to conventional construction remain substantial” for investors, including a lack of long-term durability data, uncertainty over the resale of these properties, and caution from insurers.
Additionally, one of Japan’s most common long-term mortgages requires a minimum 70-square-meter (753-square-feet) floor area for detached houses, which “excludes most current units from standard financing,” says Katano.
“(That) confines the buyer pool largely to cash purchasers and retirees, until either the products grow or the financing rules adapt,” he adds.
Japan has invested heavily in automated construction since the 1980s, and launched the “i-Construction” initiative in 2015 — a collaboration between government and private sector to digitize the sector and integrate IT solutions into construction machinery. In 2024, the initiative was extended into a second phase, targeting a 30% labor reduction by 2040.
“3DPC plays a crucial role here as a technology that directly materializes digital data into physical space,” says Ishida. These technologies could also attract young talent to the sector, transforming construction from a “demanding, dirty, and dangerous” job into a “creative, cool and challenging” one, he adds.
Although 3DPC can’t close the productivity gap on its own, Katano says that in combination with other technologies — such as prefabrication (a $26-billion market in Japan in 2025, according to YCP), AI-driven design, and autonomous heavy equipment — there are potential productivity gains of up to 40% by 2030.
Meanwhile, Kizuki is working on creating a “3DPC Academy,” which it plans to launch later this year, to train operators for a future where 3D printing will be the new normal.
“Construction tech — especially 3DCP — is still often perceived as something almost futuristic, even science-fiction-like,” says Igarashi. “It is only when people see real construction footage, hear the story behind it, and engage in direct conversation that they begin to recognize it as a real business.”
