Are we on the cusp of a 3D-printed housing revolution?
Need a home? Just press print.
3D printers are increasingly providing a cheaper, greener and faster alternative to home building. The individualized designs and walls, which are made of stacked thin layers of concrete, are popping up everywhere, from a 100-house community in Georgetown, Texas to a single-family home in Borneo, Malaysia. In a time of skyrocketing housing prices, and growing concern for sustainability, 3D-printed houses are changing from niche gimmick to a potential mainstream housing solution.
“It has been an exponential take off,” said Marchant van den Heever, technical director of Harcourt Technologies, which distributes 3D printers and related equipment to companies in the U.K.
3D printing offers potential solutions to major challenges for the U.S. housing market: reducing the greenhouse gas emissions causing climate change and rising housing prices contributing to surging homelessness. Some experts expect the American industry to boom in the next two to three years.
Despite rumors that these houses can be built for just $10,000 and in as little as 24 hours, the reality is not quite that revolutionary. “There’s a lot of misinformation out there,” said Justin Kinsella, CEO of Harcourt Technologies. “We saw some crazy stuff, where there are guys saying you can do a house for $10,000 and you can do it in two days. There is no such thing as that.”
But 3D-printed houses are already 5%-10% cheaper than a regular build in the United States, according to Zach Mannheimer, CEO of Alquist 3D, which aims to build affordable 3D-printed homes to serve lower-income communities, and experts predict costs will go down as the industry expands. A 2018 study in the academic research publication IOP Science: Materials Science and Engineerings, based in the U.K., argues that 3D printing can cut costs by at least 35%.
While a home with all its windows, doors, and utilities cannot be built in 24-48 hours, it is possible to print the walls in that time. Industry specialists say that the final product can be ready in as little as a month and a half, as opposed to the six to eight months it takes to build a typical house.
Though they were first invented in the 1980s, 3D printers became popular in the 2000s. They have little in common with the home or office printers that write in ink on paper. Imagine a robotic pipe with a nozzle at the end, sort of like a squeeze bag used for spreading icing on a cake. Instead of being moved by a human arm, the pipe is attached to scaffolding and programmed to move in a specified shape. These printers are commonly used to make components for larger machines, limbs or organs for use in education, and more recently, masks, respirators, valves and more for the COVID-19 pandemic.
Integrating 3D printing into mainstream housing construction means radically overhauling the way homes are built. A typical house is made by pouring concrete into a foundation and building a rough framing of the walls and floors out of wooden planks. Builders then install basic plumbing and electricity before adding insulation and the final surfaces to the walls and floors.
For a 3D-printed house, they still need the concrete foundation for stability, but then the walls go up immediately using slightly thicker forms of concrete that will hold up as the printer goes around. The printer is programmed to leave perfect cutouts for windows and doors. Though a multi-story house is slightly more complicated, there are successful examples, including a 3D-printed apartment building in Germany. No wood panels or bricks are involved.
In some cases, the printers are brought to the site, while in others, the houses — or components of the houses — are built off-site and transported to the location. There is still some discussion in the industry about which system is preferable.
The U.S. is in the midst of a housing crisis, with housing prices rising by double-digit percentages per year. Although the shortage has more to do with regulations that restrict new housing production rather than the cost of building new homes, the need for cheaper housing and the rising production capability of 3D printing could help the industry get off the ground.
Some experts caution that 3D printing will not be growing quickly in the housing sector in the immediate future. “This is not going to change the industry next year,” said Robert Dietz, chief economist at the National Association of Home Builders. “We are still talking about very small demonstration projects. ... My expectation is that this kind of construction is likely to scale up slowly.”
Dietz said that any innovation that improves productivity is valuable to the building industry, and that the technology could help address the current U.S. labor shortage.
However, the NAHB predicts 3D-printed houses will constitute a small portion of the market because the majority of houses in the U.S. are made with wooden frames. “We tend to think of 3D-printed homes as a subset of concrete-framed homes, which are just 10% of single-family homes,” Dietz said. “So it’s a small share of an already small share.”
If scaled up, 3D-printed buildings are significantly better for the environment than those that are built from scratch on-site. The building process cuts waste by 60% because it only manufactures the materials required. There’s no need to trim or subtract excess materials so they aren’t sending unused wood, concrete or glass for window panes to the landfill, according to academic research. And 3D printers work better with nontraditional cement alternatives such as “hempcrete” — a mixture of hemp, sand and other materials — than they do with regular concrete. That could encourage the concrete industry to pursue more sustainable alternatives to concrete, which creates significant greenhouse gas emissions in its production.
Despite those advantages, of the 912,000 single-family houses built in the United States in 2021, almost none were 3D-printed. Mannheimer estimates that just 10 3D-printed houses were built last year. The first ever commercial permit to build a 3D-printed house was given in February 2020 and the largest community 3D printed homes in the world — 100 of them, designed by the renowned Danish architecture firm BIG — is in the early stages of construction in Texas.
Although the technology hasn’t yet become mainstream anywhere in the world, the globe is dotted with 3D-printed buildings. The earliest ones were produced in the late 2010s. The first was a 3D-printed residential building in Yaroslavl, Russia, in 2017. An office building in Dubai was built the same year, and a house in Copenhagen was completed in 2018. As the technology has developed, more countries have developed both models and usable homes. Japan built a model pod-shaped house for just $25,500 in 2021. Canada is home to Airbnb’s first 3D-printed home, the world’s first 3D-printed school is in Malawi, and Kenya is planning to build 52 affordable houses. There’s a printed house resembling a submarine in the Czech Republic, houses and an apartment building in Germany, and a series of five homes in the Netherlands.
“The technology is not yet mature or commonplace enough,” Mallikarjuna Nadagouda, a researcher with the Environmental Protection Agency, wrote in an email to Yahoo News. “There are no codes or standards relating to manufacturers or specifications, and very few design professionals know how to design, specify and procure these for commercial clients.”
The primary barrier is access to, and mass production of, the right types of materials. But the industry also wants more investment in research and an increase in education programs to build a workforce.
The first hurdle — access to more suitable materials — is also what makes this industry potentially more sustainable. Traditional cement, which is also known as Portland cement, is the source of 8% of the world’s CO2 emissions because of the extremely high heat required to mix cement into concrete. It is also not the ideal consistency for 3D printing. This incompatibility has pushed the industry to seek out alternatives, which also happen to produce little or net-zero emissions.
“In terms of sustainability, finding the appropriate environmentally friendly material for this technology remains the biggest challenge associated with 3D-printed construction,” said Nadagouda.
The material used in the printer has to strike a delicate balance: liquid enough to join with the previous layer but hard enough to hold its form once it’s printed. It also needs to stay wet enough for the next layer to join with it in the time it takes for the printer to come back around.
Portland cement cannot immediately hold a strong structure. “[Portland cement] sits inside a wooden box until it hardens,” said Charles Overy, director and owner of LGM, a company that provides 3D printing software, modeling and design assistance. “But when you print concrete it has to hold itself up right after it comes out of the printer.”
It’s still possible to use it, but it’s not ideal. In response, the industry has started developing alternatives such as “lava-crete,” which is a combination of pulverized red lava rock, cement, and water. Geopolymers, which are a grouping of minerals, are also a popular alternative among 3D printing companies. All of these alternatives emit significantly less greenhouse gases than Portland cement. One study shows that hempcrete, which emits no carbon in the creation process, can store carbon as well.
“The sustainability right now, in my opinion, is partly a byproduct of not using Portland cement,” said Overy. A rise of 3D printing in the housing market might provide an incentive for concrete companies to start producing greener alternatives that are more suitable for 3D printers in order to serve that market as well as traditional construction.
Companies are also trying to source their materials locally, which could reduce the emissions caused by transporting materials. COBOD, the world’s largest supplier of 3D printers around the world, has the capability to mix any combination of materials needed to make a reliable cement alternative. In the U.K., Harcourt Technologies is already using this technology to source locally and mix on site. “In a way, it’s open source,” said CEO Kinsella. “You can use [COBOD’s] machines in the center of London or in Timbuktu and you can use whatever aggregates are locally available, obviously within normal concrete criteria.”
Developers say they are increasingly in need of a workforce to bolster production. The 3D printing industry requires someone to operate the printer, designers who understand the mechanics of printing, and people with a chemical background who can develop alternative materials for printing. Some companies are working on instituting six-to-eight-week courses in local colleges. Alquist 3D is partnering with Virginia Tech to create a 3D construction curriculum. In the U.K., Building for Humanity is starting a similar training course at Rossendale College.
Some consumers might worry about whether a house made from 3D-printed hempcrete can withstand intense pressures such hurricanes. Developers say that government grants for studies showing that they can would be helpful. In September, the New York Times reported that a series of 3D-printed homes in Nacajuca, Mexico, have tolerated extreme conditions, including a 7.4-magnitude earthquake. But more research is needed.
“Some 3D-printed homes can withstand hurricanes, floods or fires under lab testing conditions claimed by many companies. However, these claims need to be verified in real-time situations, which will take many years,” said Nadagouda.
If 3D-printed houses demonstrate that they can handle harsh environments, the speed of construction could make 3D-printed housing helpful in responding to humanitarian crises. “3D [printed] housing may certainly be beneficial during emergency situations such as natural disasters,” said Nadagouda.
“Every 3D printing company has talked to someone in Ukraine,” said Mannheimer, adding that his company was in conversations with people in Puerto Rico and Florida following hurricanes there.
Dietz, along with several experts in the industry, warned that local building codes will also slow down the proliferation of 3D-printed housing, as each local government has a different set of rulings governing safe construction. “We see modular construction at much higher rates in European countries because they have national codes and national rules,” said Dietz, referring to a more general category of houses which are pre-fabricated and usually built in a factory. “Whereas here, it’s each individual jurisdiction. That presents a challenge in terms of scaling up.”
In May, President Biden launched a program to promote 3D-printing technology as a housing solution in the U.S. The initiative, called Additive Manufacturing Forward (AM Forward), called on large manufacturers in the U.S. to pledge to buy 3D-printed parts from U.S.-based suppliers and reduce their dependence on overseas factories. While this may be a good start to government support, it does not address the need for research or better access to materials. None of the people interviewed for this article had heard of AM Forward and it is unclear what impact it has had since. The White House did not respond to a request for comment.
HUD seems optimistic about 3D-printed houses as a climate change solution. “3D printing is one of the promising advances in construction which the HUD team sees as having the potential to lower housing costs and increase energy efficiency and resilience,” a HUD spokesperson told Yahoo News in an email.
“There are sustainable materials and techniques being developed, but it is still experimental,” said Nadagouda. “The technology is still in its infancy. It has not been tried and tested, making consumers reluctant to choose 3D housing. ... Over time, the techniques and technology will be refined, and may become commonplace, but for now, it is just too early in the development cycle.”