D printing can potentially be a faster and cheaper method of building homes. But it may require more than technology to take these dwellings mainstream.

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To make housing more affordable in the U.S., we need more of it. Millions of additional units, by most estimates.

This shortage of housing has a range of complex causes, but the high cost of construction — which rose even further thanks to pandemic-driven labor and supply constraints — is definitely not helping.

An idea from the tech world holds the potential to make the building process more efficient: 3D printing. Startups have been experimenting with the technology in large-scale construction, and now there’s a push to take it mainstream.

Marketplace’s Meghan McCarty Carino spoke with journalist Rachel Monroe, who took a deep dive into the topic in this week’s issue of The New Yorker.

The following is an edited transcript of their conversation.

Rachel Monroe: What we’re mostly talking about is these printers that are making the shell of a building. So the wall system, using typically, like, a concrete mixture that’s coming from a nozzle and essentially printing the house layer by layer from the bottom up.

Meghan McCarty Carino: Is it actually printing on the site? What does the actual printer look like? You said it’s a nozzle?

Monroe: It’s a nozzle mounted on a gantry crane. So what you do is you have sort of three parts — you have a software system that’s kind of feeding the plan into the printer, which is kind of following the plan set out by the software. And essentially, like, a fancy concrete mixture, that’s blending the material and feeding it into the printer, which is just sort of tracking the outline of whatever building you’re hoping to print.

McCarty Carino: Right, and so the actual printing material is kind of a mush of different things?

Monroe: Yeah, which is a good way to put it. It’s got to have this, like, complex balance of it has to be liquid enough to move through the machine, right? But then it also has to set up quickly. So by the time that the printer head, that nozzle, comes back around, it’s solidified enough that it can kind of accept the next layer, right? And so it’s typically used as, like, a concrete or cement blend. To the layman’s eye, it just looks like concrete, but it’s got a bunch of additives in there to sort of make it precise in this way that they need it to be.

McCarty Carino: So you profiled this Austin [Texas]-based construction startup called Icon that is using this technology. What’s their pitch?

Monroe: I think the advantages became really clear during the pandemic, when we had these major supply chain issues and also labor crunches. That’s been, like, an ongoing issue in the construction industry. 3D printing is a way to ideally build houses more quickly with less labor, less waste, and the houses themselves are ideally more resilient, more energy-efficient and less expensive. But what’s interesting that’s happening right now is that Icon is printing an entire neighborhood of about 100 homes. At this point, it’s like we’re actually seeing, OK, can this be mainstreamed?

McCarty Carino: And they definitely sort of couched their mission in the very, kind of, tech utopian ethos, right?

Monroe: Yeah. This is a venture-funded company. And so you get all of that kind of world-changing rhetoric. You know, “We’re going to print houses by the millions. This is going to revolutionize the built environment.” A lot of really heady talk.

McCarty Carino: And you actually got to spend a night in one of those test-case 3D printed houses. What was that like? What did it look like? What did it feel like?

Monroe: Yeah. So it wasn’t one of the houses that’s being printed in this development. This is sort of a fancier house that Icon has printed as kind of an argument for a 3D printed architecture that you can make, like, a luxury home with this stuff. And I mean, I gotta say, it was nice. It was sort of a strange experience. The house itself has very particular architecture. They wanted a house that could only be printed, right? And so printers have an easier time with doing curves than they do a straight line, so this was a very, kind of, sinuous building. And the walls of a 3D printed house had this, like, ribbed texture because of those layers that I was talking about. So it was interesting being in there. I think I expected a house printed out of concrete, you know, made by a robot, to be sort of cold and precise, but it was cozier than I expected.

McCarty Carino: Is this approach to printing houses anywhere close to being scalable?

Monroe: You know, the promises that Icon likes to make are really thrilling and exciting. But when you look at where we actually are, we’ve got, like, a yearlong process to print these 100 houses. And I think that the federal government estimates that the housing shortage in the United States alone is, you know, on the tune of, like, 4 million houses, right? So if it’s marginally better, marginally faster, marginally more resilient, those are all good things. But the problem that we have is so much of a bigger problem than can be fixed by exciting new technology.

McCarty Carino: And how expensive or cheap is it to print a house? I mean, at this point, does it actually save money?

Monroe: This is really tricky and hard to get concrete numbers on, forgive the pun, but the best sense that I could get is that the houses that they’re printing, you know, which range from pretty simple structures for nonprofits that house unhoused people, to these luxury homes, to these kinds of standard suburban houses, [they] tend to be around 10% cheaper at this point. So you know, that is a savings. It’s not a revolutionary savings. The idea is, those savings are going to be greater once the technology moves along.

McCarty Carino: Are there specific sorts of uses for this technology that seem particularly promising? You mentioned a couple of different uses. There’s maybe tiny-home camps for unhoused people. Is this, you know, something that could be really useful for accessory dwelling units? Or are we talking about, you know, multifamily buildings?

Monroe: At this point, it’s mostly being used to print single-family homes. And that tends to be what it’s best suited for. It’s hard to do multiple stories, right? So it’s not great if you’re thinking about, like, having a radically dense built environment. 3D printing, at least the way it is now, is not going to get us there. But for the smaller structures, and particularly it’s most efficient when you’re trying to print a number of things kind of in the same general area. And the thing about it that’s kind of exciting and different from maybe other, like, modular, prefab building solutions, is that each one can be different. Because it’s just the software, it’s just as easy to print any design. So you don’t have this thing where every house looks exactly the same. You can have some variability in there.

McCarty Carino: I guess the big question here is, is this solving the right problem in the housing market? I mean, is there a technological solution to the affordable housing crisis?

Monroe: Yeah, I had a really interesting conversation with the housing expert who made, I think, a great point, which is that people keep coming up with these technological solutions for what is fundamentally a political problem, which has to do with, you know, zoning and where do we build this excess capacity that we really need? And in some ways, you know, technology is really tempting as a solution because it helps us sort of imagine that we can kind of innovate our way out of this problem without having to give anything up. Unfortunately, I don’t think that that’s how it’s going to work.

If you’d like to actually see how this 3D printing process works, watch this video from Art Insider at a building site from a different company called Alquist.

It really is like Monroe said — a nozzle excreting out a concrete mush, layer by layer, almost like watching a pastry chef frost a cake.

She also mentioned that 3D printing tech has some limitations when it comes to building up, like we typically need to do in dense cities, but there have been improvements on that front recently.

NPR reports that a company in Houston is building what designers say is the first 3D printed two-story house. It’s about halfway done, which is when my printer at home typically jams or runs out of toner.

Via MarketPlace.org