“What housing needs is a General Motors.” -- Leo Grebler, father of modern housing economics
Leo Grebler called for auto-like assembly line production of new homes back in 1973. But the new-home business came the closest to that method even earlier: in the 1940s, ‘50s and ‘60s, when Levitt and Sons built some 140,000 inexpensive houses along the Eastern Seaboard and elsewhere.
The Levitts broke down the construction process into 27 steps, and specialized crews repeated their jobs from one house to the next. Every third or fourth house was exactly the same. Even the landscaping -- two trees in each front yard, each placed exactly the same distance apart -- was identical.
At the time, Levitt was building up to 180 houses a week when most builders averaged four or five homes a year.
Nowadays, only a handful of residences are built entirely in a factory. Many more are built with factory-built components, such as floor and roof trusses, that are delivered to the building site. But no GM or Ford Motor Co. has emerged to take the industry by storm.
Not that people aren’t trying to industrialize the process, using 3D printing, robots and other technologies that are a far cry from those Levitt and Sons employed.
Today, much of the talk centers around robotics. But for the most part, advances in that field have been limited to commercial construction. For example, a Pittsburgh company has an autonomous rebar-tying robot, which can cut labor costs in bridge deck construction. In San Francisco, another outfit is selling robotic upgrade kits for heavy construction vehicles so they can operate independently of human drivers.
More relevant to housing, New York-based Construction Robotics has developed a bricklaying robot that can lay 3,000 bricks in an eight-hour day, as opposed to roughly 500 for a human. But it works best for multi-family buildings and other larger structures. Smaller walls would need to be built in a factory and driven to the construction site. And a Japanese government-owned research facility is working on a bot that installs drywall (though it’s just in the prototype stage).
Printers seem to hold more promise for housing. What is said to be the first 3D-printed house in the country was unveiled in Austin, Texas, last year by nonprofit New Story and sustainable-housing startup ICON. Now, the team intends to use the technology to build an entire community in El Salvador, housing more than 400 individuals.
Also in Austin, architectural firm Overland Partners has offered a series of proposals for 3D-printed neighborhoods. Teaming with ICON and nonprofit 3Strands, the collaboration wants to address the housing crisis and give disadvantaged families a sense of community.
While 3D printers can extrude plastic, metal or concrete, ICON uses a proprietary, secret cement-based mix that allows it to “rapidly print homes that are beautiful, structurally sound and cost-effective,” the company says.
Gary O’Dell, CEO and co-founder of 3Strands, agrees, saying that these innovations “will allow us to drive down the costs of building and operating new homes and, in turn, reduce the stress of housing in people’s lives.”
American researchers and entrepreneurs aren’t the only ones pursuing new technologies. Last year, for example, a French family of five was reportedly the first to actually inhabit a 3D-printed, 1,000-square-foot house. And in the Netherlands, multiple partners have come together to erect a five-house project using 3D printing.
In Switzerland, meanwhile, researchers have developed robotic and 3D-printing technologies to build a 2,150-square-foot, three-story smart house. It includes a digitally designed and 3D-printed floor slab, plus a casting system that digitally pours concrete into flexible frames that shape the pour as it hardens. A robot builds timber frame modules by following a computerized layout, and an on-site construction robot assembles the parts based on a sensing and computing system.
According to Land Lines, the publication of the Lincoln Institute of Land Policy in Cambridge, Massachusetts, “the advantages of this still-evolving form of building include more efficient use of materials, which both cut costs and minimize waste; speed of construction; and potential for customization.”
Finally, we can’t forget academia, which also is trying to push the construction envelope. Take Clemson University’s newly patented Sim(PLY) system, which is best described as a cross between a do-it-yourself kit home and a 3D puzzle.
Developed by faculty and students, the system allows a house to be built without the use of power tools or nails. Not even a hammer is necessary, according to the school. The various pieces are held together by steel zip-ties.
The technique calls for off-the-shelf plywood to be cut by routers into interlocking tab-and-slot pieces that fit together to form a solid, tight frame. Pieces can be fabricated anywhere, then shipped flat-packed to the construction site, ready to be assembled by hand.
“Unlike traditional framing systems, which generally require onsite cutting and other operations that require expertise in the construction process, Sim(PLY) streamlines assembly to the point that no advanced construction knowledge is required,” said a release from the university. And since the plywood pieces are not nailed, the resulting structure can be disassembled, modified and reused elsewhere.
Prototype Sim(PLY) houses have been built and tested in South Carolina. Now, the system is set to debut commercially in British Columbia as part of an effort to build affordable housing for teachers, nurses, police and firefighters.