Many inventions, in hindsight, feel more like discoveries. Think of the bicycle, or the steam engine, or glass—all simple and useful enough to be widely copied once they were known.
Another such invention, 3-D printing, is now scaling up. All over the world, an impressive diversity of people and organizations, ranging from startups and hobbyists to construction and engineering firms, are successfully prototyping 3-D-printed buildings.
The government of Dubai has set a goal of 3-D printing 25% of every new building by 2030. Prototype single-family dwellings have been 3-D-printed in China, Italy, Russia—and Texas. Global infrastructure firm
uses 3-D printing to prefabricate jail cells and hospital rooms. Arup, a construction engineering giant in Europe, is testing a variety of such “additive manufacturing” technologies, in materials ranging from concrete to stainless steel.
This technology is still nascent. It isn’t about to disrupt the approximately $10 trillion global construction market. It can’t instantly solve housing crises or radically shrink building costs. It could remain a novelty, the 21st-century equivalent of the geodesic dome.
But the more you examine the basics—the way the technology could potentially save energy, materials and time—the more it starts to feel like an idea that just might work.
Meanwhile, architectural-scale additive manufacturing is yielding experiments that might directly benefit both the world’s richest and poorest people.
An Italian architect and a housing activist in El Salvador don’t have a lot in common, aside from both having radical plans for combining robots with the Romans’ favorite building material—concrete.
Massimiliano Locatelli, founder of architecture firm CLS Architetti in Milan, has just finished 3-D-printing an 1,100-square-foot, single-family dwelling to be unveiled April 15. He partnered with Arup and the startup CyBe, which makes a portable concrete 3-D printer.
The printer extrudes cement in much the same way a desktop 3-D printer extrudes plastic: A print head attached to a robotic arm moves around and around, depositing one layer at a time, until a structure grows up from nothing.
In love with the aesthetic of 3-D-printed buildings—unfinished, they look like layer cakes or exposed sedimentary rock—Mr. Locatelli says he’s most enthusiastic about using 3-D printing to shape retail spaces inside of larger buildings.
For Lisselot Tronconis, the appeal of 3-D printing isn’t aesthetics, but that it can cut the cost, time and labor required to build homes. She wants to use 3-D-printed buildings to increase the number of houses she builds every year for some of the world’s poorest people—families in the sprawling suburban slums of El Salvador.
Ms. Tronconis is the executive director of the charity People Helping People of El Salvador and the local program manager for El Salvador of New Story, which has partnered with Icon, an Austin, Texas, 3-D-printer construction startup. Using traditional methods, New Story has already built more than 800 homes world-wide, including 200 homes in El Salvador for families who previously lived in single-room shanties made of timber and sheet metal.
Currently, a cinder-block house requires about 15 days and $6,500 to build. Printing a home instead is projected to take 24 hours, cost $4,000 and use half as much iron rebar, a New Story spokeswoman said.
Icon printed a prototype home in Austin and has tuned its process in anticipation of conditions and materials available in El Salvador. Still, unknown challenges may arise when the first New Story house is printed later this year, the spokeswoman said.
Fundamentally, 3-D printing with concrete is a modern update of incredibly old building technologies, says Rick Rundell, a senior director at Autodesk, which makes design and engineering software popular among architects, engineers and contractors. All over the world, our prehistoric ancestors made homes from mud, adobe, cob and similar materials, building up their walls one layer after another. Their structures shared many of the same advantages of modern 3-D-printing: They were strong, cheap, locally sourced and minimized waste.
While concrete is by far the most widespread architectural-scale additive-manufacturing material, it isn’t the only one. In Nantes, France, a team of university researchers printed a home out of both concrete and foam. Researchers in Sweden, the U.S. and elsewhere are attempting architectural-scale building with cellulose, glass and a variety of novel composite materials.
On March 31, Amsterdam-based MX3D unveiled a stainless-steel pedestrian bridge made by a robotic arm with a welding apparatus attached. Rather than being printed from the bottom up, it was printed from one side to the other, one millimeter-thick molten blob at a time.
It took a team of four industrial robots 11 months to print the bridge, which has a span of 12.5 meters and weighs approximately 12,000 pounds, says Tim Geurtjens, MX3D co-founder and chief technology officer. With 10 robots working simultaneously, he estimates he could print another one like it in just 10 days.
Other companies pioneering similar 3-D-printing construction techniques are Apis Cor, based in Russia; China’s Winsun; and Contour Crafting, which leased a 33,600-square-foot facility in El Segundo, Calif., where it is currently working on a mobile 3-D-printing robot for concrete.
Site-printing buildings may be new and still only barely tested, but using 3-D printing in prefabricated construction—where pieces of buildings are made in factories before being shipped to a construction site—has been used at AECOM since 2011, says Russ Dalton, the company’s building information modeling director for the Americas.
By 3-D printing jail cells out of concrete, for example, AECOM can precisely place openings for plumbing and other fixtures, which is key to keeping the cells secure.
As in manufacturing, the main challenge to 3-D printing for buildings is that existing techniques for making things are already pretty good. This could confine the new approach to niche uses.
However, 3-D printer construction could find applications where there is little market for current techniques, owing to cost or other difficulties. That might mean housing the world’s billion poorest people, but it could also mean erecting fantastical, currently impossible-to-build structures in the deserts of the United Arab Emirates—or for astronauts on the moon.