The cost of building a new house has gone up sharply over the past year. Not just because of lumber, but because steel, insulation, windows and appliances are all harder to get and more expensive because of high demand and delays. A number of startups have promised to revolutionize construction with new materials and technologies. It’s not easy — the modular construction startup Katerra filed for bankruptcy earlier this month.
But there are others looking to disrupt the housing industry. I spoke with Sam Ruben, the co-founder and chief sustainability officer of Mighty Buildings, which uses an enormous 3D printer to build houses inside a warehouse in Oakland, California. The company is set to deliver its seventh house this week. The following is an edited transcript of our conversation.
Sam Ruben: Many of the companies in the space are using 3D-printed concrete or mortar. What we’re using is a proprietary material called Light Stone. And what’s really cool about it is that it cures using light. So as it’s coming out of the nozzle, we hit it with high-powered ultraviolet light, which immediately hardens it. That it allows it to support its own weight, meaning that not only can we print the floors and the walls, but we can also do unsupported spans, opening up the ability to print the roof and ceiling. Additionally, it means we can do things like print curves and unique shapes as well as creating traditional aesthetics.
Scott: So you’re the chief sustainability officer, why do you see this kind of building as more sustainable?
Ruben: Where we’re able to really hang our hat, currently, is on the fact that we’re able to eliminate over 95% of the waste that would normally be produced during the construction phase. Here in California, that ends up being about one ton of carbon per one of our 1,200-square-foot units. Outside of California, that jumps to almost three times, just because of how much recycling California does.
Scott: How do you do that? How do you reduce that waste?
Ruben: Well, that’s one of the great things about 3D printing — we only print what we need. So we’re not in a situation where we’re taking a 12-foot two-by-four, cutting it down to 10 feet and then tossing that extra two feet.
Scott: Now, these houses are not cheap. I was looking at your price list. It costs at least $187,000 for a 350-square foot studio. That’s pretty small. If you’re not offering more affordable homes, what is the selling point here?
Ruben: Yeah, so one thing about that number: What that number represents isn’t just the unit itself — the unit itself is only $115,000. That also includes all the foundation, the site, utility, trenching, landscaping afterwards, everything that’s needed. And here in the California market, yes, it’s not inexpensive. However, compared to similar quality units, we’re actually seeing 20% to 40% savings against traditional stick-built of similar quality. And one of the things that’s important to realize for where we are right now, is that we’re not targeting affordable housing, we’re actually targeting the missing middle. So your teachers, your firefighters, people who serve our communities, but more and more can’t afford to live in our communities, particularly in incredibly high-cost areas, such as the Bay Area here in California. And we’re in the process of developing our first multi-story offering — three-to-six story townhouses and low-rise apartments. And with that additional units coming to scale, we’re hopeful that we can actually address truly affordable housing, particularly here in California and the Bay Area, where a single unit of affordable housing costs $750,000. But to address that more broadly, as we move into areas outside of California, our plan isn’t to ship from here in Oakland, because shipping in California, construction costs would be silly. So our vision is actually a distributed network of Mighty factories around the country and around the world that are in areas where we have builder-developer partners, where we have volume, and that will allow us to not only produce houses for those markets, but also produce jobs.
Scott: Could this technology be part of the solution to the shortage of affordable housing, both the missing middle that you mentioned, but also, truly affordable?
Ruben: Yeah, I definitely think so. And I think that’s where the move into multi-storey and really being able to create density becomes important. Because, again, we’re looking here in the Bay Area with a cost of $750,000 for a single unit of affordable housing, being able to reduce that cost by using our technology, and also speeding up the delivery time, which is part of the cost factor as well, because one of the things we’re able to do is produce the units quickly. And we can produce one of our studios in a matter of a week or two, while the foundation is being poured on-site. And so being able to have that speed and be able to deliver that quickly increases the time for the return on investment. So it actually can allow projects that might not pencil out by accelerating the time that the investors are able to start making their money back. So that opens up opportunities for affordable housing that might not be possible with more traditional and longer timeline projects.
Scott: It seems that you also have an opportunity to disrupt the culture of construction, which has been a traditionally male industry. You and all your co-founders, I noticed, are men. Are you bringing women into your company as well?
Ruben: We are, and that’s something that we’re actually very focused on, because we do recognize that we have four white guys as our founding team. And so diversity, equity and inclusion is something that’s very, very important to us. We’ve actually recently hired a construction manager — an African American woman. And we’re actively in the process of hiring a female structural engineer to add to our engineering team. And even before that, we already had many, many women throughout the team, particularly on the R&D side, leading our material development team, leading our design development team. Additionally, sales and our marketing and PR teams [are] led by women, so it’s something we are taking very seriously. And additionally, in terms of our production team, obviously, this isn’t specific to women, but we have made a commitment to hiring locally here in Oakland, and also creating a pathway to jobs for formerly incarcerated individuals. We’re really working hard on increasing our diversity and also providing pathways for historically marginalized communities to enter the construction field. And not just the construction field, but the high-technology construction field.
Related links: More insight from Amy Scott
One barrier to more widespread adoption of 3D-printed homes is trust, which is why Mighty Buildings worked with the industrial certification company UL to create the world’s first building standard for 3D-printed construction. Ruben said if something were to go wrong with a 3D-printed home, it would set back not just the company that built it, but the whole industry.
Though Mighty Buildings says it’s not targeting affordable housing, others are. Habitat for Humanity is building its first 3D-printed home in Tempe, Arizona. The company ICON printed its first 350-square foot home for about $10,000 in 2018, and has since built villages of tiny homes in Mexico and Austin, Texas.
And while nosing around on the larger topic of 3D printing, I found a story from this month in National Defense Magazine about the U.S. Army’s efforts to develop the world’s largest 3D printer that makes metal objects. The goal of the Jointless Hull Project is to create a printer large enough to produce the exterior of a combat vehicle in one piece. The machine will be able to print parts up to 30 feet long, 20 feet wide and 12 feet high. The lead contractor is ASTRO America, which says the technology will reduce costs, weight and production times for military vehicles while increasing “survivability.”