Brick by Brick
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Brick by Brick
3D Printed Homes: A Concrete Solution to the Shortage?
If the U.S. builds as many homes as it did last year, experts predict it will take an average of seven and a half years to close the housing gap. How do we speed up construction? One way might be to increase the production of 3D printed houses. This technology is starting to take off in Texas and a few other states. Could it make sense in other parts of the country?
Interview guests: Interview guests: Sandy Curth, PhD researcher who designs and builds sustainable 3D printed structures; Dr. Ali Memari, director Pennsylvania Housing Research Center and Penn State Bernard and Henrietta Hankin Chair in Residential Building Construction; John Smoll, owner Open Vision Builders
Ann Thompson:
Can 3D printing add more housing in record time?
Sandy Curth:
The way we build buildings is way too slow. We basically need to make buildings twice as fast and that's just not possible with current technology. And so these other more experimental things like 3D printing, we have to give them a shot.
Ann Thompson:
Robotic arms squeeze out concrete like toothpaste, building everything from tiny homes to million dollar ones. A development of 100 homes in Texas is getting creative with its designs.
Conner Jenkins:
The printer doesn't care if it's printing a straight line or a zigzag or a curve, right? So you can kind of open up your imagination and not be restricted by time or cost.
Ann Thompson:
A handful of states are taking the lead in this computerized construction. One Ohio developer is trying to make strides.
John Smoll:
It's really hard to think about. You can build actually cheaper, you can build it faster, and you can build a better quality product.
Ann Thompson:
Is it time for this automated technology on a larger scale?
Ali Memari:
There is a future for 3D printing in general, but it has to find its own niche and be part of maybe the bigger fleet of robotic construction
Ann Thompson:
Today on the pod 3D printed houses, the time it takes to build one, the cost, the materials, and how well they withstand extreme weather. Let's get into it. This is Brick by Brick Solutions for a thriving community.
Ame Clase:
Brick by Brick is made possible thanks to leading support from AES Ohio Foundation, Greater Cincinnati Foundation and George and Margaret McLane Foundation, with additional support from Laurie F. Johnston, Murray and Agnes Seasongood Good Government Foundation, The Robert & Adelle Schiff Family Foundation, and more. Thank you.
Ann Thompson:
Hello and welcome to Brick by Brick, where we're highlighting solutions for a thriving community in southwest Ohio. I'm your host Ann Thompson. Picture this a construction site with a foundation and one or more 40 foot robotic arms going back and forth, printing the walls of a house just like this layer by layer.
(sound of robotic arm)
Ali Memari:
When the concretes travels through the host, it gets to a nozzle. Nozzle has a head just like imagine, like a toothpaste tube.
Ann Thompson:
Dr. Ali Memari is a professor at Penn State specializing in residential building construction. He's also the director of the Pennsylvania Housing Research Center and has studied 3D printed houses.
Ali Memari:
There's no waste of concrete. Okay, you just print as you need. It is faster than labor, basically is less. There's some other advantages like you wanted to build a house or a building that has curve, a horizontal curve or vertical curve.
Ann Thompson:
Memari is excited about the technology, but as you'll hear later, the researcher sees more negatives than he does positives. Modern day fully permitted 3D printed houses start to emerge in 2018, but historians say the world's first 3D printed building can be traced to an Indiana inventor. In 1939, William Urschel's wall building machine used an automatic ramming mechanism to compress the concrete between spinning discs. This consolidated and smoothed each layer as it came out today there are only a handful of construction companies. 3D printing houses ICON in Austin, Texas is one with a hundred homes in a single development. They range in price from 450 to 600,000. 75% of them have been sold. This Old House took a tour of ICON’s, house zero, valued at nearly a million. In the show. The company's senior project manager, Conner Jenkins, stands in the living room looking at the concrete bead.
Conner Jenkins:
The next option would be just to paint it, which we do on many of our projects. Another a really popular option to cover the walls is plaster, and this home actually has plaster on the walls in the bathrooms. Tile is an option.
Ann Thompson:
Each ICON home is made from a mix of concrete powder, sand, water, and additives churned out of a 40 foot robotic printer, a single printer does the job of more than a dozen construction workers. And ICON now has 11 robots. Each one can print a core structure in about 24 hours, hundreds more. 3D printed homes are planned in Texas, and Icon is looking to outer space. It has a $57 million contract with NASA for its construction system to build 3D structures on the moon and beyond back down on earth. An Ohio developer is testing interest in 3D printed homes north of Dayton and Brick by Brick’s Emiko Moore reports on what thrust him into the market.
Emiko Moore:
Behind me, workers are building a 3D printed home, and right now they're filling the concrete walls with spray foam to improve energy efficiency. John Smoll, owner of Open Vision Builders with over 30 years in the construction industry, wasn't sold on 3D printed homes when the concept was brought to him, but his partners in sustainable concrete innovations wanted to test it out. Building Ohio's first 3D printed home in Wapakoneta.
John Smoll:
As we printed the first house, as the walls were going up, my skepticism was coming down. It's very reasonable to think about building a 3D printed home within a month
Emiko Moore:
And instead of three to five years to train someone to build a conventional home training for 3D. Printing a home takes just a few weeks. Many young adults are experienced with using 3D printers.
John Smoll:
They know more about it than I do when it comes to that. I understand the housing, how to build a house, they understand how to make the house. And so I said that's a game changer and that's really what brought me on board. I got really excited about it when I recognized that we actually now have something that can move the needle on affordable housing and affordable for many different reasons.
Emiko Moore:
Small says he's amazed by the interest from different fields. One hire Benjamin Howard, who now does a lot of work, came with no construction experience.
Benjamin Howard:
I'd say it takes about two weeks just to get the basics down. That's just all the real basic stuff to be competent at it. I'd say just a couple months is really all it takes. It's very simple overall. And if you have a background in computers and stuff like that for modeling, setting up models with CAD and BIM which is building information modeling, then yeah, you can absolutely do it very, very quickly.
Emiko Moore:
Also, rapidly growing is development and sustainability research in concrete.
John Smoll:
We need our concrete to be hard in about three to five minutes. So from the time it extrudes from the nozzle within about 60 to 120 seconds, that needs to be hard enough to support the layers that are building upon it. So we print a wall section, a nine foot tall wall, and we do that in 45 minutes.
John Smoll:
We're getting a lot more faster cements. And one of the things that we're doing now is we're actually starting to use a cement that was it's zero carbon footprint basically because it's created from fly ash, which comes out of coal mines, right? So we're using, again, a sustainable product that we didn't know that we were going to be able to get into.
Emiko Moore:
Construction sites are easier to maneuver since the 3D printer only takes an eight by eight foot space.
John Smoll:
A lot of these communities have lots that are infill what we call urban infill, which is primarily why we bought the robotic printer because it needs a very small footprint. So now I can go in and print next to homes that are existing on very small lots and build small homes that are affordable. So we bring a generator on site, which another cool thing with that is we're completely off grid, so we can literally take this anywhere and build anywhere. So on a mountain side in a third world country that has no infrastructure, we could do that all on site.
Emiko Moore:
Today, Smoll is currently finishing a second 3D printed home in Lima, Ohio that he and his wife plan to live in.
John Smoll:
It's a very durable and strong structure. It also has concrete columns that come down the wall within sight, within the wall and the wall cavity. So wind resistance, hail resistance, debris in a tornado in theory, much more durable
Emiko Moore:
And easy to add textures to the walls.
John Smoll:
For me to print a wall that has some design to it, maybe curves or arches, very easy to do and doesn't add to the cost. So it's something that would in conventional construction would cost a lot more
Emiko Moore:
Over time Smoll anticipates the cost will be 15 to 20% less than conventional construction. And the key to affordability is building smaller homes that can adapt over time
John Smoll:
Down the road. If you need a little more space, you can add a little more space without having to have that massive mortgage up front.
Emiko Moore:
Small says many cities have been receptive including Lima.
John Smoll:
So that's where we'll be actually doing some concept homes that are in that seven to 800 square foot range. Hopefully this year we're thrilled about that, that we get to use our local community as a stepping stone to hopefully make this work throughout the state.
Ann Thompson:
Thanks for that Emiko. That was really interesting. I'm wondering how do people pay for these?
Emiko Moore:
There's still a lot of educating that they have to do with banks and appraisers, insurance companies and lending officers, so they were able to do that for John Smoll, who's building his home now in Lima. He said he was able to get a construction loan for that. And then I also asked him about getting insurance for it, and he said a lot of insurance companies, they love the idea because these homes are more fireproof, they're more weather resistant, but a lot of insurance agents have gotten really hit hard with all these disasters, so they're a little more risk averse. They're a little harder to get insurance companies. He was able to find a couple companies in Ohio that have embraced it right now, and he said the ones that have, they gave a 40% less rate and that he had someone who did even do research. And that 3D printed homes will reduce insurance claims by up to 40% more. It's still all relatively new, but these are some good signs for potential home buyers.
Ann Thompson:
Lots of things to consider. Thanks for that Emiko.
Emiko Moore:
Thank you
Ann Thompson:
A year and a half ago, there was a lot of excitement surrounding a 3D printed home in Michigan built by the nonprofit Citizen Robotics, TikTok influencer Trey Little showed it off.
Trey Little:
This is the first 3D printed house in Michigan and it's located in Detroit. It costs $224,000, which costs more than the average house in Detroit. But the goal is the more they print these, the cheaper it'll be for construction costs. Would you move in one of these?
Ann Thompson:
That's the question. Would you? In 2023, the Alper Real Estate group, spent over 200 hours combing through builders, webpages, videos, news articles, and more to do an industry study. It determined for 3D printed homes to take off, prices must come down, building codes must adjust, and large builders need to invest in robotic printers. It estimated by the end of that year, 3D printed homes would number in the one thousands. States driving the technology include Texas, California, Oregon, Virginia, Florida, New York, and Arizona. The report says affordable 3D printed housing in the US hasn't begun on a large scale, but research and proof of concept builds are underway coming up on Brick by Brick, Do 3D printed buildings have to be made out of concrete and should they an MIT researcher? No, but he remains cautious about how quickly his model can ramp up.
Sandy Curth:
I hesitate a little bit to suggest that this is some kind of solution to mass housing in a rapidly developing or urbanizing city in say like Nairobi, which is growing super, super fast.
Ann Thompson:
That's ahead on Brick by Brick.
Ame Clase:
Brick by Brick is made possible thanks to the generous support of so many, including Diane and Dave Moccia, P & G, The Camden Foundation, The Stephen H. Wilder Foundation, Rosmary & Mark Schlachter, a donation in memory of Frank and Margaret Linhardt, The A. T. Folger Jr. Lowe Simpson Fund and more. Thank you. We couldn't do this work without you.
Mark Lammers:
When we talk about thriving in our neighborhoods, I tend to think about sustainability because any improvements we make, we want them to endure. Right? Hi, my name's Mark Lammers and I'm the executive producer for Brick by Brick. And while our team stays focused on exploring and uncovering the next viable solution to what ails us, we're looking to you to help hold us accountable and keep this thing sustainable. And while a donation does go a long way at CET and ThinkTV in this case, we're just asking for a little time and feedback right now. There's a big green button on our website and a link in the podcast show notes to our audience feedback form. We'd be so grateful if you shared your thoughts about the work we're doing so we can keep improving and connecting solution minded neighbors like yourself with the social responses that will move our cities in the right direction. Your feedback also helps us seek funding to keep this effort going. We appreciate your time and can't wait to hear from someone in every neighborhood. Thank you.
Ann Thompson:
Welcome back to Brick by Brick. Concrete isn't very environmentally friendly, making it releases large amounts of carbon dioxide into the atmosphere and it absorbs and retains heat, which can lead to higher temperatures in cities. So we wondered what other materials are being considered PhD candidate in architecture. Sandy Kirth develops ways to make 3D printed buildings more accessible, sustainable, and affordable, going beyond the concept of traditional 3D printed homes. Welcome back to Brick by Brick.
Sandy Curth:
Thank you so much. Really happy to be here.
Ann Thompson:
We keep hearing about concrete. Is it the best material to use?
Sandy Curth:
I argue that it is not primarily because concrete has a very significant climate impact and it's often not a very healthy material to make a building out of. So if you're simply making a small single family home, you don't really need the strength of concrete because you're not supporting a 20 or 30 story building, and it's very hard to change a concrete building once you've printed it or cast it in place. So other materials I find a little bit more compelling.
Ann Thompson:
You have developed methods that use other things, so what are they and how do they work?
Sandy Curth:
So my area of research is essentially 3D printing buildings out of low carbon, locally sourced materials. So things like earth, different types of soil, which you might end up with from the excavation part of a construction project where you're excavating for the foundation. We often take all that material and pay a lot of money to truck it to a landfill. Believe it or not. We put a lot of dirt into landfills, but that material when calibrated or adjusted a little bit can actually be a really good building material and have really good thermal properties and also has a very low climate impact and is of course a very cheap because it's just dirt.
Ann Thompson:
And is that material the primary area of your research or are there other materials that you've been studying?
Sandy Curth:
That's my primary area, but I experiment a lot with different kind of low climate impact materials. So for instance, my family farms oysters, so I've done a number of experiments where I take oyster shell waste. So after you go to the oyster bar and have all your oysters, you have all these extra shells which are basically made out of calcium. And calcium is actually what we heat up to create cement. So you can take a bunch of oyster shells and put them in an oven for a little while and make a kind of cement. So to make the earth in construction stronger, I've tried essentially recycling oyster shells into a type of cement to stabilize the earth and make it a little bit more weather resistant and that kind of thing.
Ann Thompson:
So hearing about mud and straw and oysters, it kind of makes me think about the three little pigs story. How well do these materials hold up to hurricanes, tornadoes, earthquakes?
Sandy Curth:
Bottom line, they hold up very well actually. It really just comes down to design. So I think this is an interesting and common trend in the world of 3D printed buildings or new approaches to buildings. The technology can do a lot, but it can't take the place of just designing a good building. So for instance, there are earth and buildings made of nothing but earth and a little bit of straw that are 11 stories tall that have stood in Yemen for 1200 years. So they're buildings that have been continuously inhabited for at least 1200 years, maybe a little bit more. Some people think it's more like 1500.
Ann Thompson:
Yeah, that's incredible. So we all kind of have a picture of the nozzle of the traditional concrete coming out in 3D, printing the building. So how does the dirt and straw and shells concept work? Is it the same way?
Sandy Curth:
Very similar. It's actually a lot easier than 3D printing mortar because trying to get a concrete or mortar mixture to come out of a nozzle and then instantly become hard enough to support another layer of that material is very hard and it requires a lot of very complicated chemistry, which frankly often doesn't work in a normal construction site. So you have to wait for the perfect weather or you have to wait until you have the right time of day and it be in the evening whether it isn't too much sun because the heat will change the behavior of all those chemicals. So you see all these videos of buildings magically coming to life through 3D printing, but the reality is most of them are very sped up and shot over the course of many weeks. So when people say we 3D printed a house in a day, what they usually mean is 24 hours over three months, which is an important distinction. There are some buildings that are going up much faster than that, but they're still pretty rare. It's an emerging technology.
Ann Thompson:
How affordable is this technology and can it be replicated pretty easily?
Sandy Curth:
Yeah, so that's exactly the kind of area of research that I work in. So just to put actual numbers on it, my house building 3D printing system cost about $50,000. Some of the pieces were recycled, so the main kind of robotic component of my particular system used to work on a car assembly line, so it's a big robot arm that was building cars in Detroit, and I convinced MIT to purchase it for me off of eBay. And there's many, many hundreds of machines exactly like that available around the world that can be easily retrofitted into 3D printers. And that's something I find kind of exciting.
Ann Thompson:
Tell me about the houses or buildings that you've built using that equipment and where have you built them?
Sandy Curth:
The first building I made was back in 2018, I think in Colorado. So I was working with some researchers at uc, Berkeley, and we built a number of small buildings, one of which you'd probably call a house that had three little rooms made from soil that was sourced from within about a hundred yards of where we made the building, which was very exciting because it was really hyper-local material. And then I've made during my PhD a number of smaller scale experiments that are really meant as demonstrators, so more of systems like a six by 10 foot tall piece of a wall that has certain thermal properties that we wanted to test. And then we put it outside for a year and put a bunch of sensors on it and kind of observed it over time. But most recently, I'm currently in the middle of making a small building. It's about 400 square and it's just a single story structure, but what we're doing with it is making it so it's thermally passive. So for the environment we're printing it in, which is Southern California, in theory, it shouldn't need AC or a heater in the end because of the way we're using the flexibility of the printer to make shapes inside the wall that trap air and kind of control insulation in different ways.
Ann Thompson:
Where do you see your technology and materials going? Do you see this expanding to countries that maybe don't have a lot of money in Africa other places? And I'm wondering what you could get the cost down to.
Sandy Curth:
I'm working here in the us there's some people in Spain, there's some people who I believe are currently in Kenya. There's a company that's been trying to three print earth in buildings there that was started in Kenya. Where else? There's also some people in Portugal in the UK, so there's people all over the place. And what I would say is that yes, this is a technology that could in the future be useful for making very low cost buildings. I hesitate a little bit to suggest that this is some kind of solution to mass housing in a rapidly developing or urbanizing city in say Nairobi, which is growing super, super fast. I don't know if this technology is quite there yet where that's actually really going to be helpful in that context. But what I will say is that trying to make buildings with this technology in Southern California has been really interesting because there there's really complicated building codes.
You have earthquakes, you have fires, you have all kinds of extreme weather. And so it's a really good test bed to confirm that, yeah, not only could we make a temporary small building that somebody could live in, but we could make a real house that meets all of those building codes. And I think if we can do that, then it's kind of exciting and we can start to suggest, oh yeah, maybe we could take these machines somewhere else. Maybe we could share the plans for these machines with people in other countries and they could start to use them, basically make it a democratizing accessible technology. That's really the dream.
Ann Thompson:
Well, we'll be following your research, Sandy Curth, thanks for being on Brick by Brick.
Sandy Curth:
Thank you so much. It was great to be here.
Ann Thompson:
You heard Sandy mention one of the limitations to building a 3D printed home out of concrete, the difficulty of getting the consistency just right. Here's an example. In Athens, Tennessee last year, it took a company 45 days to 3D print an 8,000 square foot expansion for a Walmart because extreme heat and humidity C clogged the hoses. Here's another problem, Dr. Ali Memari says, there is no established building code. That was one of the difficulties in Michigan. The Detroit House took more than a year to build as Citizen Robotics fought an uphill battle with code policies and practices and had to reinforce the walls with more concrete because D walls weren't allowed to be load bearing. What about the cost to build in the Detroit neighborhood where the 3D home was built? The average price of a traditional home is $82,000. The 3D home cost $265,000 to build, but the selling price was capped at 225,000 in 2018.
The academic publication IOP science said 3D printing could save as much as 35% compared to a traditional built. But the Texas Real Estate Research Center reported the cost savings are only for constructing the walls and in stick-built homes, framing is the fastest and cheapest part to complete. Dr. Memari echoed that saying the 3D part is only for the walls, and then it becomes like every other house with potential delays and higher costs. Plus there's the risk of concrete cracking and colder temperatures. Icon told this old house that cost of its homes is on par with traditional builds. Maari says so far the turnkey approach like Icon is delivering with a complete house is the best method. Otherwise it doesn't make sense. One limitation for builders is the cost of a 3D robotic printer, about $800,000. In some cases, they're in the process of developing proprietary material, which takes time and money.
Some builders and advocates are charging ahead. The United Arab Emirates want to have 25% of all new buildings constructed using 3D by 2030. The West Japan Railway Group just built a small train station shelter in two and a half hours. And an Oklahoma lawmaker is proposing the state's housing tax credit include 3D printed houses. 3D homes require fewer construction workers, although those workers do have to be highly trained in robotics. The California company Mighty Buildings uses a stonelike material cured and printed with an ultraviolet light that is stronger and lighter than concrete resistant to mold, mildew and insects and can weather an earthquake, which is nine on the Richter scale and a category five hurricane. Do 3D printed houses have a solid future?
Ali Memari:
There is a future for 3D printing in general, but it has to find its own niche and be part of maybe the bigger fleet of robotic construction.
Ann Thompson:
And it's unclear when that might take off on a bigger scale. We want to hear your housing story as Brick by Brick develops more episodes. Go to our website, cetconnect.org and thinktv.org where you'll find a big green button to give feedback. We have lots of resources for you including related articles, a link to the podcast, our TV docuseries, as well as online extras. It's been a couple of weeks, but we finally have the team back together again for the takeaways and I'm glad about that with Emiko and Hernz Laguerre Jr.
Hernz Laguerre Jr.:
Hey everyone, we haven't done this in a minute.
Emiko Moore:
Good to see everyone.
Ann Thompson
As we're thinking through all the many things related to 3D printed housing, what are your thoughts, Ako?
Emiko Moore:
Well, it's interesting because you often think of concrete homes as possibly boxy or cold and sterile, but Hernz and I went to visit one in the first one that was built in Ohio and and the exterior is really very modern and very stylish. It was surprisingly very nice.
Hernz Laguerre Jr.:
Yeah, definitely different than what I expected. I like the design capabilities that 3D printed homes have, so I personally like it.
Ann Thompson:
And those curves are a lot more economical with concrete than they would be for wood, let's say. And it doesn't
Emiko Moore:
Add to the cost. You've got a lot of curves and designs that are already factored in with the cost.
Hernz Laguerre Jr.:
Yeah, you feature Citizen Robotics and the 3D printed home they have in Detroit. I had an opportunity to speak with the chief product officer for the organization, Fernando Bales. He told me that essentially everyone, every builder wants to build at the lowest cost per square foot. And to do so sometimes there's a lot of negative decisions that have to be made, but automated home building could help lower the cost and help make the process quicker. But we saw with another form of automated building with modular building, that's not necessarily the case because the home up in Detroit is less than a thousand square feet, this two bedroom house, and it costs around $225,000. So not the most cost effective home.
Ann Thompson:
Yeah, the economies of scale. And really when we're talking about 3D printed homes, it took me a while to figure out, oh, we're just talking about the walls. Everything else is kind of like a traditional home. You still have the plumbers, the electrician, people putting on the roof, so that's something to consider. Also if you live up north. Wonder about concrete cracking.
Emiko Moore:
That’s right, he said that they plan for that if they put in expansion joints just like they do on brick structures. So they're controlling the cracking. It's natural and concrete, but they just make sure that they have it in predetermined areas. Good to know.
Ann Thompson:
And if you're having problems picturing these 3D printed houses that we're talking about, just know we have some pictures in our web articles that we've written online. So go to cetconnect.org or thinktv.org. Thanks guys.
Hernz Laguerre Jr.:
Cool. It's good to be back together again doing these takeaways
Ann Thompson:
For sure.
Emiko Moore:
It sure is.
Ann Thompson:
That's our show. If you like what you hear, please rate and review our podcast. It helps make it easier to find. We hope you learn something and if you did, please tell your friends and family about it. For Emiko Moore and Hernz Laguerre Jr. I'm Ann Thompson. We'll be back soon with more solutions. Take care.
Our show is produced, hosted an edited by me, Ann Thompson with reporting and story editing from Hernz Laguerre Jr. and Emiko Moore. Our Executive producer of Mark Lammers. Our show consultant is Gloria Skurski. Gabe Wimberly is our audio engineer and mixer. Zach Kramer runs the lights and cameras. Derrick Smith is our production specialist and Jason Garrison is our production manager. Kellie May heads up our marketing and promotions, along with Mike Shea and Bridgett Dillenburger. Elyssa Stefenson handles the website and Steve Wright is our designer. Bill Dean and Andres Kruza are the engineers for the show and our Chief Content Officer is Colin Scianamblo. Our music is from Universal Production Music. Brick by Brick: Solutions for a Thriving Community is a production of CET and ThinkTV, Southwest Ohio PBS member stations.