In a previous article on the GovDesignHub, we sat down with Peter Evans, assistant professor of industrial design at Iowa State University, to discuss an exciting program that is exploring the use of 3D printing to reduce the cost of construction and make affordable housing a reality across Iowa – and the rest of America.
This is especially important in America today, where the COVID pandemic, low-interest rates, and other factors converged to create a massive spike in housing prices over the course of the last few years. In fact, according to the Federal Reserve Bank of St. Louis, the median home sales price in 2022 was $428,700 – an increase of $58,900 from just a year ago and a 30% increase from 2020.
Working closely with a consortium of education, state and local government, and industry partners, this Iowa State University-led program is studying the impact of 3D printing and other automation technologies on home construction. The organizations are looking to evaluate if these new technologies can create viable, structurally-sound housing for low-income Americans at more reasonable prices.
In the second part of our conversation with Pete, we go more in-depth on the technologies used to build the 3D-printed houses, discuss the timeline for the project, and discuss the role that digital design plays in the construction of these homes.
GDH: Can you tell our readers a bit about the technologies that enable the 3D printing of houses?
Pete Evans: Sure, if you looked at a plastic 3D printer on a desktop, there are a variation of those types of machines and larger machines that follow some of those same precedents.
There are exoskeleton 3D printing machines that have a box built around them out of a lightweight metal truss. Then the printer operates, moving around within that box. There’s another type of 3D printing machine that’s called a flying gantry that not only moves within that space, but the entire system is on rails. What’s interesting in that particular case is that you could extend those rails and keep printing like a train.
There are challenges with both technologies, thinking about how to level the machine and get it to print predictably. These machines are also working with a very sensitive material in this current use, where most of the technologies use a pumping system, which includes a mixing element. It’s similar to what you might see on a construction site where the dry cement mix includes cement, sand, aggregate, and water. But unlike a regular construction site, the material gets pumped, which brings up special considerations.
This type of material requires some additional elements in addition to the robot. For instance, how that material gets mixed, when the material gets mixed, how the material is delivered, or if other robots need to be added. These considerations will continue to change as the automated and robotic building site evolves.
“At the end of a construction process, you have something that is called an “as-built condition” because as you go through a process, everything usually happens approximately like it’s supposed to, but that might deviate from the construction documents, so you go through a process to define what happened.” — Pete Evans
GDH: Aside from the 3D printers, what other technologies play a role in these projects?
Pete Evans: Another critical piece of technology is geospatial or GIS technology. The ability to start to understand how automated and robotic technologies tie into a digital survey provides new opportunities where you know where the buildable area of a site is in a digital simulation, as well as working with surveyors and measuring the property or lot lines physically.
On top of that, to get to more of a construction-level tolerance, we’re starting to work with drones and a technology called photogrammetry. That technology allows us to two-dimensionally and three-dimensionally scan the site, which can include the construction of a home. But we are digitizing the entire process to understand what is happening, what will happen, and what has happened.
At the end of a construction process, you have something that is called an “as-built condition” because as you go through a process, everything usually happens approximately like it’s supposed to, but that might deviate from the construction documents, so you go through a process to define what happened.
We’re trying to investigate whether we can use that process to start defining the site at the beginning. We want to understand what has to happen to modify the site and the robot on the site. Then we can print, modify, build and fabricate this construction. Afterwards, we can verify all that information all the way through the entire process with the drone.
All of these types of technologies can impact the residential construction space. They are impacting some larger commercial construction projects today in kind of piecemeal fashions, and that’s where we are trying to investigate. We can apply this on a pretty small scale where we can wrap our hands and head around all of these technologies to say, “Okay, this is a small scope problem. Let’s see if we can really change how this is done.”
“We can build on those opportunities and ask some fantastic questions that are at a more complex scale and hard to see. I think that the larger projects we see winding out today benefit from all these things I’m talking about already” — Pete Evans
GDH: What role does digital design play in this project? Do digital design solutions like CAD or BIM play a role in the actual construction or 3d printing of the houses?
Pete Evans: Digital Design is a central tenant for this project. We are thinking that we could change some of this process from what has been a CAD-driven, and on occasion, beginning to be a BIM-driven set of documents that have allowed us to work with contractors and get projects built, but actually have that information go all the way from CAD and BIM through computer-aided manufacturing (CAM).
By putting things like a 3D construction printer on-site to develop and construct the house, we’re actually changing what has historically been described as design intent, and we’re giving instructions to the machine to build the construction of the actual house. This fundamentally changes the relationship from what has been handing off a set of construction documents on paper and saying, “Here’s what I’d like to have built,” and then a contractor has to figure out all of the materials and go after it and get it accomplished.
I think this type of opportunity again, where we’re dealing with a house, we can understand everything at the very beginning before anything happens. One of the promises of BIM is to avoid conflicts down the road, avoid change orders of magnitude, and dodge mistakes and errors. Using all of those capacities for conflict and clash detection and using the digital model of this house to enable environmental simulation, costing, and material takeoffs, all sorts of very pragmatic opportunities are there.
We can build on those opportunities and ask some fantastic questions that are at a more complex scale and hard to see. I think that the larger projects we see winding out today benefit from all these things I’m talking about already. But we have a need in the affordable housing area that we are not addressing with these capabilities. These robots immediately provide us with this opportunity to jump into this small-scale but necessary typology and start to impact it in a very dramatic fashion.
“This collaboration will be the first demonstration of this technology for our project. Again, it’s not the first 3D-printed house that has occurred… We’re not the first, but we are trying to attack this opportunity comprehensively and objectively” — Pete Evans
GDH: What is the timeframe for this project? When will we start to see houses built and moved into?
Pete Evans: We will build a house, and some of that plan is even evolving over the past year, but we’re looking at directly working with Brunow Contracting in Hamburg. They have a 30-unit development that they’re responsible for, and the state has asked Brunow to allow us to work with them on a house by the summer of 2023.
This collaboration will be the first demonstration of this technology for our project. Again, it’s not the first 3D-printed house that has occurred; they exist in Texas, California, Virginia, New York, Florida, New Jersey, and more I think. We’re not the first, but we are trying to attack this opportunity comprehensively and objectively.