Our planet is already home to more than 8 billion people, and that number is expected to hit 10 billion by mid-century. All those people will need places to live—and there’s already not enough affordable housing for the people that live here now.
What will it take to meet that demand? Pick whichever stat gets your attention: You could say that we need to build 13,000 buildings a day, or 2 billion homes by the end of the century. You could say that we’ll have to build the equivalent of a Paris every week—or a New York City every month. Or you can simply say that we can expect the number of buildings on earth to double in the next forty years.
But even if our traditional approaches to residential construction could keep up with that demand (which they can’t), there’d still be a problem: construction generates 11% of our global greenhouse gas emissions. And construction generated 600 million tons of landfill waste in 2019, up from 170 million tons in 2009.
To meet growing global demand, we need to build more housing more quickly—and it needs to be both more affordable and more sustainable. Incremental improvements won’t be enough—we need a radical reimagining of residential architecture.
One approach that might work? 3D printing. The New Yorker just published a piece on ICON, the Texas-based startup that is developing technology to 3D print homes. ICON uses a proprietary cement mixture they call LavaCrete to extrude the walls for single family homes in days or weeks, rather than months or years needed for traditional processes. Working in partnership with leading U.S. home-builder Lennar, the company is currently finishing work on the first 3D-printed residential development in the U.S. just outside Austin. They previously completed a similar development in Nacajuca, Mexico, in collaboration with affordable housing innovator New Story.
Julieta Moradei, formerly Head of Research & Development at New Story and currently a founder at HomeTeam Ventures, which was an early investor in ICON , shared the work on the Nacajuca development in the AU Theater. “We believe that innovation in construction is critical in order for us to address the issues in affordable housing,” Moradei said. “Construction is the largest market in the world, it holds 13% of global GDP, yet it is the least digitized sector. It’s at the very bottom of all industry sectors, right above farming. It only invests 0.5% of its value into research and development. So we know there’s a huge opportunity to innovate in the construction sector and that it has a direct ripple effect on us being able to build more affordable housing.”
Computation, complexity, and additive approaches
ICON’s approach to 3D printing whole structures from concrete is one way to go, but there are other ways to use additive technologies, as Mania Aghaei Meibodi, assistant professor of architecture at the University of Michigan, points out in her AU 2022 Theater talk.
One approach uses computational design to 3D print “smart slabs” that have the structural strength of traditional slabs but use 60% less concrete. In another, Meibodi and her students printed a 500-square foot house out of plastic and carbon fiber in only a week. “This is not only weatherproof, it also withstands natural disasters such as flooding,” Meibodi says. “And you can fully recycle the material at the end of the lifecycle of the building.”
She has also shown the role that 3D-printed thermoplastic formwork for casting can play, enabling complex, multi-functional designs—and also greater design freedom.
“With thermoplastic 3D printing, we have the opportunity to rethink the building envelope,” Meibodi says. “You’re in control of surface detailing, thickness, weight, interior features—every detail at every scale. And this would allow us to integrate the conventional functions of an envelope—like cladding, insulation, services, moisture barrier, air barrier—into one single manufacturing system.”
“Achieving this complexity and control over interior features is only possible with 3D printing,” she says. “And this will open new territories in design, providing options that we didn’t have before.”
Modular, prefab, and beyond
3D printing isn’t the only way to solve for the intersecting requirements of scale, speed, quality, affordability, and sustainability. Callahan Tufts shared the work of innovator Nexii in the AU Theater at AU 2022. Using their proprietary building material, Nexiite, an alternative to steel and wood, they create modular building panels that can be assembled rapidly by small teams. Their process reduces carbon impact and construction waste, while accelerating the building process by 75%.
Using their process, a crew of five put up a two-bedroom house in four days, according to Tufts. Another project, a free-standing coffee shop, was assembled in six days. “We were able to meet all the environmental goals for this prototype building, 20% less embodied carbon, and there was no red listed product in it,” Tufts says. “We had 43% reduction in greenhouse gas emissions during our production process. And in the end, we kept about 13,000 pounds of waste from the landfill.”
The need for transformation isn’t up for debate—the only real question is which processes will prove the most effective in helping us transform the industry. But whether you’re talking about additive approaches, modular systems, or another approach altogether, there’s one thing they all have in common: they all rely on digital workflows.
As Mania Meibodi points out, “Digitization is reinventing construction and it is introducing new design opportunities for architects.” We can’t predict the future of residential architecture precisely, but we can be confident that we’ll use digitized processes to build it.