300 houses built by 3D Printing

Revisiting a housing development consisting of 300 3D Printed homes.

Revisiting a housing development consisting of 300 3D Printed homes.

Foreword by Ian Thompson, Editor

3D printing houses has been discussed and employed as an innovative building method for quite some time. We’ve observed a few sporadic projects where developers are printing 2, 10, 20 houses, and so on. However, for me, the printing of 300 houses on a single site signifies an industry milestone, reinforcing that this building system and method are here to stay – primarily, in my experience, in North America and Europe.

If you’re aware of other countries investing in this innovative technology on such a grand scale, please feel free to correct me.

For anyone seeking an example of how far behind some countries are in adopting better building systems and practices, New Zealand stands out as a prime case of being stuck in the dark ages. I was informed by the owner of a New Zealand 3D printing company that their imported 3D printing system could only be used to print a wall on the ground and then hoist it onto the foundation slab – that’s all that the Council has permitted them to do so far. This approach, in my opinion, defeats the entire purpose of the exercise, removing the efficiency and savings that this technology provides.

For some, it might take a while to appreciate this building method and style. Its uniqueness is evident, but the ability to 3D print your kitchen bench at the same time as your walls forges a seamless integration between the structure and its fixtures and fittings. This is just the tip of the iceberg, folks. New 3D printing materials are entering the market, and the equipment is evolving at a rapid pace. The only limit to this technology is your imagination – and, of course, professional, regulatory, and consumer awareness.

As ever, our thanks to Matt Risinger from the USA based Build Show for contributing his videos to our audience.

Video Transcript

I’m Matt Reisinger, and I’m Will King. Where are we today, Will? We’re touring over a hundred 3D printed houses here at Wolf Ranch. Holy cow, this is pretty cool. We were here before, checking out these walls getting printed, and now they actually have a finished model home. We’re gonna go meet my buddy Connor and get all the details. And believe it or not, in the six months we’ve been here, a bunch has changed. 3D printed homes, let’s get going. Thank you. [Music]

Oh my goodness, is this wild! Have you ever seen one of these before? Oh, this is incredible. What is this? It’s just all concrete. So this is 3D printed concrete. It’s got that really cool look, very iconic, no pun intended. Uh, and then this one’s a model home, so it’s been fully painted.

There he is! What’s up, Connor? Hey, Matt, good to see you. Last time I saw you, this was a little rougher, and it’s looking like a real home now. I’ve got some lipstick on it, don’t we? It’s nice. Hey, it’s finished. Well, good to see you. Will’s the builder down in Alabama who shoots videos for me on buildshownnetwork.com. He’s never seen one of these; he’s seen my videos, so I thought, let’s give them a tour of your mom while it’s available. I’d love to show you around, and maybe you can teach me some stuff as well. Well, mine’s bowling already, so you’re already cool. Let’s go catch us up to speed.

This is your wall system, but Lennar is actually the builder in this community, right? Yeah, Lennar is the GC on this project. We’re collaborating with them and the BRCA Ingles group to design and build these homes. So it’s been such a collaborative and great process. Lennar brings so much experience to the table in helping us scale up to develop this technology into something that we can share with a broader audience. And then the BRCA Ingles group is bringing an amazing design aesthetic that hopefully is blowing those minds. I mean, the design is pretty killer. What did you say when you first walked up? I noticed the exterior immediately, just like, yeah, all the metal roof details with the edge on the roof. We’re calling it the knife edge. The knife edge is cool, but it’s hard on that detail. It creates a really, really sharp aesthetic but also is really good against the weather. So we’re really proud of that one.

Now you guys are the concrete guys, though. This was printed with your, you call it lava cream. I’m going to correct you; it’s not concrete, it’s lava creek, which is closer to a grout. So it has a sandy aggregate, small aggregates. You know our slabs obviously have their concrete have kind of larger rocks in them, so we print with something more akin to a grout. Okay, gotcha, but pretty high prius eye, obviously. And when it comes to Lennar’s normal houses that are wood-framed, I mean, I would have to think you’re three or four times more structurally rigid and probably even much more overall efficient than what code dictates, right? Yeah, that’s what we’re hoping to bring to the table right with the same cost, more resiliency over time, better thermal performance, better structural performance. That’s kind of where we’re trending is, you know, in all those categories, roughly three times higher performing for roughly the same cost. So we’re proud. We want to continue that trend; we want to get stronger, and we want to perform better thermally and continue to reduce our cost over time.

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So, for Will, who’s not been here, let me explain this, and you tell me if I’m wrong, correct me if I lie here, okay? Your walls have, if this is an exterior wall, an inner wall, and an outer wall, and they don’t touch each other except maybe they get close to touching where you have window and door locations. They are separated. They’re separated. They’re too proud of that. You have a little wood bucket, baby, yes. So you can set kind of standard flanged windows, but then you fill, or I… you don’t, but Lennar fills the cavity with open-cell spray foam that’s been poured in. Yeah, ICON does do that portion that’s in our show. You show you that, okay. Yeah, and so we collaborated through the entire finish-out. You know, you can imagine for cabinet makers and countertop people and electricians, this is all very new, so we’re really involved. It’s been again a great collaboration. So we almost consult with Lennar kind of throughout the process.

But just to kind of wrap up what you’re talking about, we have a four interior gap in the middle that we use for rough-ins, plumbing, electrical. We can get into that. This is the first project where we’re fully including electrical and plumbing in all of the walls. Oh wow, so that’s a good innovation for us. And then after that’s all done and the roof is dried in, we spray in open-cell foam that’s moisture-resistant, typically used for CMU construction. It’s kind of a similar application, and that’s how we get that high R-value, by using that insulation in the air cavity.

Connor, I don’t think that’s a fair comparison between this house and a standard, let’s say, stick frame house that’s 2×4, 2×6 construction because every 16 inches you’ve got a stud that’s maybe R4, and then in the cavity, you’ve got R15 maybe with 4 inches of open-cell spray foam, right? But here you’ve got that continuous wall, and when that interior wall gets cold, it stays there. You’ve got some thermal mass here, right? That’s you’re speaking to a real benefit of the technology. We’re using an air gap, kind of like traditional construction, but also can glean the benefits of a thermal mass wall, just like you said. During the day, that exterior wall is slowly taking heat, and then overnight, it has the opportunity to shed that, so you get a nice even thermal performance.

Yeah, and like you said, we’ve worked hard to thermally break the wall system. Our internal design team works really hard on all these details. So even at locations where you might think that is occurring, it’s not. So like window bucks, door bucks, we’ve worked on a detail that is thermally broken, and then we’ll install things like a wood buck so that the experience of a window installer is kind of similar to what they’re used to. It changes tape things like that. Yeah.

Now, Will, if you guys don’t know, was a former firefighter. I was in the fire service a long time. When you come into this house and compare this to a wood-frame house with wood framing on the floor and wood-framed walls and ceilings, what do you think about this house? I mean, there’s a whole lot less fuel here, right? So we leave the fuel load for a fire. We’re significantly less in this house. Have you done any fire ratings on your walls? I’m assuming we have. We’ve done some projects where we’ve printed kind of smaller units and some townhomes that have a demising wall. So, as you all know, that’s important for that. We’ve done some fire raining, and we’ve landed right at that two-hour fire rating. So the wall system itself can act as a fire-rated demising wall as long as you’re using the right caulk and things like that.

You’re also speaking to resiliency. I’m going to keep going back to that. You know our mission is to drive down cost and time, but really, an added benefit to the system is the resiliency factor. Something Jason, our CEO, talks about a lot is what the walls don’t and do want to do. And what they don’t want to do is burn. If there’s a fire around, they also don’t want to get eaten by termites, for instance. They don’t want to mold. They’re not food for mold either. There are a number of things that mean that not only the material itself will be here a long time, but when it faces challenges, it stands up to those challenges over time.

And even the outside, like with all the wildfires we’ve had recently, this immediately stands out to me because we talk about the inside fire lid all day long, but we’re not going to catch fire on the outside. It’s going to be much harder for fire to spread across the house. Metal soffit, metal roof, and concrete walls. Not a lot to catch on there. That’s top of mind for me, guys. Right? I mean, obviously, we’re all aware of what’s happening in Hawaii, California, Canada. There is literally a wildfire five minutes’ drive from my home in Austin, Texas right now. I mean, you know there’s one up in Cedar Park, yeah, Matt. So, as temperatures grow globally, this is something that we’re hyper-aware of, and we want to be a part of the solution, not part of the problem. We hope to bring more resiliency because when you think about the cost of a home, we often think about the front costs, but we often forget to talk about the life cycle cost, yeah, right. How much does it take to replace that home over time? So we hope that most of these components last longer than a traditional build. That’s something I would love to talk about because Will and I do a lot of remodeling.”

“I live in a 1970s neighborhood. I ended up currently building a new house in that neighborhood because the 50-year-old houses, they’re not in great shape. I actually started to remodel my house and kind of gave up and took it back to the slab. Yeah, but if we fast forward to this is 2023, let’s fast forward 50 years from now, this house, these cabinets are going to look super dated. Yep, the appliances are going to be terrible, but these walls, minus maybe you need another coat of paint, are going to be structurally the same as they are today. So when it comes to remodelability, I’ve got to say this house is pretty straightforward. What would you do to this house in 50 years?

I mean, again, I think kitchen, bath, and paint are going to be the biggest thing. Yeah, that’s it. Luckily, we have nice big open floor plans, so I don’t really see the need for what you and I have been fighting for a long time in remodeling of tearing out big load-bearing walls. Plus, if you wanted to rip out these doors and put some fancy molded doors someday, these doors would pull right out. Your exterior windows and doors would be no big deal. Pop the trim on the outside, you’ve got room to get the flange. You could put a nice triple glaze uPVC in there someday and really upgrade the performance. You’ve got a wood frame roof that’s traditionally insulated roof that could also get changed to closed-cell spray foam. Say the roofline, maybe even some rigid rooftop foam, and you could take this from a house that already is above code today to a house that probably meets code in 2073.

You are speaking to all the benefits, and it is the benefit of starting with an open floor plan, right? It gives you more options moving forward. You know, we have already painted inside and outside of these homes, and they will easily accept a new coat. I’ll hearken back to our design team once again; they have worked really hard to actually create a booklet that instructs future homeowners on how to change out the window. Here are the steps that you take to replace it if you need. It’s a no-brainer; it’s super easy.

I gotta ask you, though, when it comes to non-issues, I know you hear this a billion times, and it probably drives you crazy, but ‘Oh my gosh, the walls are going to be all dusty, how do I deal with that?’ What do you guys, after all the million times you’ve heard that? Yeah, thank you for asking me. It’s a common question, and what I can say to start is that in our experience with all of the homes that we’ve built so far with people living in them, we have not had any issues with that, right? No feedback around kind of dirt buildup or dust build-up and needing to clean. So happy to report that that should not be an ongoing maintenance issue. Now every few years, if that needs to happen, I would imagine a light dusting would kind of go a long way. But besides that, in our experience, and we still think you’ll be talking many years before you need to do it. But if you really needed to do it, just use that shop vac attachment that has the brushes.

That being said, this guy’s never seen the printer, and I think you told me there’s some updates on the printing process. Can we see something under construction? We’re so excited to show that off. Let’s go look at it. All right, we’ll see you all out there.

All right, guys, Connor’s brought us to a house under construction. Before we show the printer, as I’m walking in here, Connor, why the spray paint on the jam here? So that’s actually liquid-applied flashing. This is how we really are making our homes bombproof. We want to create a strong moisture barrier behind any window or door installation so that when the window and door installers come in, they can focus on their flanges and their tape and focus on making that waterproof. So what you’re seeing is the benefits of additive manufacturing. If you can kind of design it, we can print it. So you’re seeing this L-shaped pocket that allows us to install pressure-treated lumber here. We then fill in the gaps in the lumber with foam and then apply liquid flashing from bead to bead. Gotta great.

Now we can see those tapcon screws, and that’s all it takes. Just put that two by PT on there, a couple tap cones, and that’s nice and solid. Is this MC cable here that I’m seeing, which is a cable that already has the sheathing on it, rather than running conduit?”

“Yep, this is the same that they’re using inside the walls, right?

They are. This is the wire they’re using inside the wall. It was, uh, in this jurisdiction, what kind of easily passed code, right, to use MC in a masonry wall. Our design team is doing a lot of good research around right now around potentially using Romex, easier to install, cheaper. So less expensive, less expensive, yeah. So we’re excited to potentially bring that to future projects. That’s pretty cool, yeah. And then later, like we saw in the model home, the interior door gets installed and that 45 trim goes on, and the rest of these details are pretty straightforward. Yeah, that’s the hope.

And I’ll kind of take this opportunity to speak to part of the benefit of the wall system because it’s important that we don’t think about this as replacing the framing, right? It’s the full wall system replacing framing but also sheathing, waterproofing, veneer, inside drywall, tape, float, texture, and all of that. Brick, there’s no rock, yeah. So then as you start to finish out the home, you get to steps that you would have normally taken, and you can kind of skip them. So an easy example is thinking about baseboards. So baseboards exist to cover up rough edges on drywall, right? Well, there’s no rough edge on the drywall, so now we don’t need baseboards, right? No base anywhere, yeah. You kind of get to steps that you can just skip, so that’s how hopefully we start to really innovate around the entire process, not just the walls.

And that brings down cost, but speaking of cost, these houses in this neighborhood start about a little under half a million, and I’m always surprised by the comments like, ‘What can we do to build these houses less expensively? Has ICON thought about that at all?’ Yeah, that has always been at the heart of our mission, is driving down time and cost, which kind of goes hand in hand. We’ve traditionally worked with non-profits like New Story and Mobile Loaves and Fishes here in Austin, and they’ve been such good partners. Recently, we’ve done something really exciting, which is open up a global design competition to design homes that we can build for less than $99,000. Wow. So that was recently enough for all costs for the house, overall cost for the house. To your point, these homes are comparable to the area, but you still need to be in kind of middle to upper-middle class. So we really want to increase the potential buyers of these homes, and so there is a one million dollar prize for that competition, and we’re already committed to building some of those homes in neighborhoods in Austin and other cities around the U.S. to get more affordable housing out there. That’s pretty cool, man.

Yeah, you mentioned cycle time. I heard there’s something new on that. Let’s go check out the printer, and we’ll talk cycle time. Let’s go look, all right.”

Now, this is where the money shot is right here, the printer going in the background. But I gotta tell you, Conor, it’s 103 right now in Austin, Texas. Yeah, how in the heck do you pour concrete at 103? Yeah, you know, we’ve made some upgrades recently to allow us to do that. You’ll notice the printers used to be gray, so anyone with a sharp eye may see that we have rolled out an aesthetic upgrade to the printers along with some hardware and software upgrades. Kind of have a stormtrooper vibe going, I like the store, that is good, the white printers reflect a lot more of that heat, that sunlight, and so it keeps the inside of the machine a little cooler, a little cooler. Even five degrees makes a difference, big difference. That’s right with electronics and with all that, oh yeah, cement throws flowing through that nozzle to the end. Now, I don’t know this for sure, but it seems to me like this machine is actually faster on a bead than when I was here last time. Is that true? Is there anything you’re speaking to the upgrades? Man, we can print faster now. We print beads that are more consistent. So this is all leading just to a better product, which we’re really excited about. We will continue to make those strides. We have an amazing team of engineers at ICON who are constantly developing new upgrades to our suite. Yeah, you guys are always doing that. What’s the printing time now? We’re at a 2,000 square foot house. How long does it take you to print this thing from the time you start on this bare slab until you’re ready for the framer to come work on the roof? Matt, at the beginning of this neighborhood, we were averaging about a month, kind of print time for this project. Now we’re at roughly two weeks and trending downwards. So that’s awesome, about a 50% reduction, that’s the beginning of this project. It’s almost faster now than the machine running now than your first model. It’s about 30% faster. So it’s a good bit faster. We’re really excited about these upgrades.

And when I say two weeks, this is important, Matt. I kind of want to get into what we’re replacing from traditional construction, right? That’s important context here. So I’m going to take a moment to say that we’re not just replacing the framing. We’re replacing the sheathing on the outside, waterproofing, and even veneer. So brick or stucco, yeah. And then the drywall on the inside and the tape float and texture. So when you think about me talking about a two-week timeline, it’s all of those scopes kind of coming in and out because it’s easy to look at and say, ‘Well, if we’re going to frame this house, my framers can throw up exterior walls, interior walls on a 2,000 square foot slab house in three days, two days.’ But it’s not that, that’s right. It’s not just framing, you’re doing so much more in that one six-day cycle time, yeah. The exterior and interior finish, both replacing with us, I think really speaks to me as a builder. Yeah, absolutely. And not only that, but you’re changing out gypsum drywall on the inside that has a paper facing with this grout lava creek, which is way more bomber, that’s it. And on the outside, in effect, it kind of feels like a modified stucco pass. That’s it, more textured masonry, yeah. And so you’re speaking to that resiliency over time, right? Not only the resiliency, but you talk about the benefits from a building perspective. You know, we’ve kind of consolidated and simplified the materials that go into the supply chain. There’s some benefit there, but also have simplified the coordination, which from a project manager for general contractors is kind of the secret sauce for us right now. How well can you get trades in and out? And when you’re only doing that with one trade instead of four or five, there’s a lot of differences. That’s a big deal, yeah.

As you walk around, this is your first time saying this, what’s the couple questions that come to mind or what have we not talked about that? Well, I mean, I think the resiliency still just speaks to me. That’s my biggest takeaway of the day is just how strong this construction is, how fire-resistant, wind-resistant. I have noticed while we’re talking about the details of these walls, what are the clips I’m seeing, these little stainless steel-looking ties, what’s the purpose of that? I mean, obviously, it’s some type of strengthening tie in the wall, but how many of those are you using? What’s the background of that? Yeah, we have three major types of reinforcement on the wall, all steel. So I’ll start with vertical. We print cores in the wall, okay? We have a double bead, and one of those beads pops out and makes this little pocket. So we epoxy that steel into the slab and then go through the roof and grout that in. So that gives us a lot of strength, really, yeah. Yeah, in the beads, we also apply two other different types. So some steel that is along the bead and it’s continuous. So we use apps there, just like you would kind of in your slab. And then what you’re referring to will are the cross ties, okay? So these are stainless steel ties that connect the veneer bead to the structural bead. Absolutely, so the wall system is strong as a unit, right? Not individual pieces. And when we’re done building that, that’s when you get your kind of bomber-proof strong wall system.

Well, that’s what makes for a strong system, I’ll say. I’m thoroughly impressed with the overall vibe here that I’m seeing. So I look forward to, I guess, seeing this neighborhood complete, yeah. Well, it’s coming soon. Connor, really appreciate that, man. How can people find out more either about this neighborhood or about ICON? Yeah, go to iconbuild.com, okay? And you can see a lot about this neighborhood, you can see a lot about our past projects, upcoming projects. We have a new initiative called Initiative 99, a global competition. Yeah, you mentioned that earlier, yeah. So that you’ll find details about that at our website. So I’ll put a link in the description for all those. A lot of exciting stuff going on, man. Really appreciate it, Connor, absolutely. Will, thanks for joining me for a fun tour, man, yeah. You guys don’t know, go check out Will’s videos on buildshownetwork.com. I’ll put links to all that below. And if you’re not currently a subscriber, hit that subscribe button below. You know we’ve got new content every Tuesday and every Friday, plus on TikTok or Instagram. Otherwise, we’ll see you next time. Help me out, Connor, the Build Show.”