Homebuilding in 3D

These new construction companies can print full-size concrete houses faster, safer and stronger while significantly reducing costs.

These new construction companies can print full-size concrete houses faster, safer and stronger while significantly reducing costs.


JOHANNES GUTENBERG, A GERMAN GOLDSMITH, IS CREDITED WITH INVENTING THE PRINTING PRESS around 1436. It wasn’t the first book printing automation — Korean bookmakers used moveable metal type a century before Gutenberg and woodblock printing in China began roughly 500 years before that. But the Gutenberg process jump-started a printing revolution, and an information revolution as well.

The printing presses of today would hardly recognize its forefather from the 15th century. A Heidelberg Speedmaster is the size of a bus, roaring through 15,000-plus large-format sheets of precision-aligned color an hour. A modern commercial printing facility is indeed a sight to behold. In the last decade, printing has taken on another dimension — a third dimension to be precise. A few Consumer Electronic Show’s ago, 3D printing took center stage and the technology began to change how manufacturers looked at prototyping. Dream it, load it into a 3D modeling program, and watch the magic happen.

What if the dream is to print something really big, like big-as-a-house big? We are in a housing shortage, with price increases putting the starter home out of reach for many families. Can 3D printing be a viable option for home construction?


One company using 3D printing technology to do just that is Long Island-based SQ4D. The company developed a patent-pending technology for 3D printing in construction applications called Autonomous Robotic Construction System — ARCS for short. With ARCS, SQ4D can print full-size concrete houses faster, safer and stronger, while significantly reducing the associated costs. The process is layering one strip of concrete upon another, building the walls up from the foundation, leaving gaps for doors, windows and mechanical. To prove the concept, the company printed a 1,900 square foot house in 48 hours of print time over an eight-day period. And it was printed and built onsite, while using less than $6,000 in materials. We caught up with SQ4D Chief Technology Officer Kristen Henry to learn more.

“These homes have great resilience, which is important in light of the changing climate and weather-related events such as flood, fire, wind and pest.”


BILL: Let’s start with the elevator pitch; what is the inspiration behind SQ4D?

KRISTEN: What we’re doing is trying to improve large scale 3D printing. The motivation behind it is the severe housing shortage the U.S. is currently facing. Material costs are increasing, the supply chain is inefficient, and affordability is declining rapidly. Our approach is to automate as much of the home-building process as we can. When we apply the concepts of automation, we see efficiencies rise and costs go down. Another benefit is the inherent safety in automation. Our process makes for a safer site, for example, reducing the amount of time on-site climbing ladders. And of course, with the shortage of construction workers, reducing the number of workers on a job site is an important advantage.

BILL: Is there a different on-site skill set needed for 3D home printing?

KRISTEN: Yes, it’s a different skill set than stick frame construction, but anyone with a machine operation background can learn it. So back to your original question, we’re building a market, proving the technology, and making it more prominent.

BILL: Tell us about the concrete, is it a special mix?

KRISTEN: SQ4D is focused on readily available materials — sand and Portland cement. The blend with water is optimized so the layer below has set enough to support the next layer above it, but still has enough adherence to attach the layers in a strong bond. It’s a balance of size and speed. Actually, a larger home with longer linear runs allows the printer to run at faster speeds without compromising the ability to stack the material. If the house is under approximately 1,000 square feet, we need to slow the machine.

BILL: What are the advantages of printing?

KRISTEN: A clear advantage of printed concrete is less waste – our design code decides how much material is needed. And while cement is a carbon intensive process, we are working on sequestering that carbon in the structure for the 50+ year life of a home. I should mention that we are looking to warranty the homes ourselves – that’s how confident we are in our materials.

Increased R-value is another important advantage. We can expand the wall cavity to increase the amount of insulation. With traditional stick frame building, a larger cavity in the wall costs more because the 2 x 6 foot boards are more costly than 2 x 4s. We don’t have that issue when printing.

BILL: These machines are obviously huge; is there a limit to the size of the structure that can be printed?

KRISTEN: Our newest machine is a modular design, so we’re able to adjust to the size of the printer. Scalability is important in both directions – some smaller sites can’t accommodate a large printer, and some projects require much taller build volumes.

BILL: Let’s talk about what designers and architects need to know.

KRISTEN: For designers and architects the process is similar to traditional building. Architectural plans can be built in 2D, then SQ4D can turn it into a 3D model, convert to G-code to be loaded into the printer. Local building jurisdictions need site plans, electrical, mechanical and such just like traditional building.

BILL: How are the local building departments responding to 3D printed concrete?

KRISTEN: Acceptance and understanding is growing; codes are not yet specifically tailored for the 3D printed method, but we are getting lots of support. And back to the architects and designers, 3D printing enables them to design with curves and interesting shapes or features that may have been cost-prohibitive with traditional frame construction.

BILL: What’s the key takeaway about the opportunities with 3D printed concrete homes?

KRISTEN: These homes have great resilience which is important in light of the changing climate and weather-related events such as flood, fire, wind and pest. And we’re looking at the materials and the potential for even more sustainability, researching carbon capture alternatives, recycled plastics, and the use of glass as a replacement for sand in the concrete. We’re really just getting started.

Alquist 3D

The motivation to address the housing shortage is driving innovation in not just the technology, but the implementation of that technology. Alquist is a new construction company using “3D printing technology to create exceptional design while lowering the cost of housing and infrastructure in economically distressed and under-served communities.” (source: www.alquist3d.com) The Alquist origin is an inspiring story in itself. It begins with Founder Zachary Mannheimer. Trained in theater, Mannheimer lived in Brooklyn for eight years running theater companies. He said, “I loved the work — organizing productions and following my goal of using theater to create community.” But New York was challenging; costs were in¬creasing and the theater community there was beginning to feel more like a homogeneous bubble.

Mannheimer left New York in 2007 and embarked on a 22-city road trip across the country to find the right place from which to make a fresh start. He decided to settle in Des Moines, Iowa and started a non-profit art center — the Des Moines Social Club — that hosted events related to the arts. Located in an old firehouse, they developed expertise in economic development. Word spread and they were soon getting calls from all over the country from groups asking for help creating opportunities to drive their local economies.

Based on the demand for this expertise, Mannheimer and his partners started Atlas Community Studios, an economic development group working in communities spread across 27 states. As they went into these communities — generally smaller, more rural markets — they learned of the issues they were facing and began building a team by adding expertise in the different fields that could help with the mission.

“Our goal is to make these 3D printed homes look like homes, to normalize and commercialize the opportunity.”


BILL: Let’s start with a little background on Alquist. You’re not from a construction background. At what point did home construction enter the mix?

ZACK: Alquist Community Studios had its own set of challenges in any given market, but housing was the one challenge that was faced by every market. A healthy housing market needs a balance between wages and costs; either you have to get companies to pay higher wages, or you need to lower the cost of housing. Companies are not always amenable to — or even able to — increase wages. But we could pursue a lower cost housing model, beginning with the construction of the home.

BILL: And you began researching lower cost alternatives to traditional construction? What attracted you to 3D printing?

ZACK: I traveled extensively and saw the possibilities of 3D printed construction. We founded Alquist 3D and got a grant to print our first 3D printed home. This really is the birth of an industry. We’re not alone in what we do, and we don’t make the technology. We’re a construction company and we use the technology to increase affordability in housing. We’ve looked into panelized and modular models. Right now, we are focused on 3D printing but believe the future might see a mix of printed, panelized and modular.

BILL: Who makes the 3D printing machines?

ZACK: There are a number, but we have developed a great partnership with Black Buffalo, based in New York. They are a provider of large-scale 3D printers for construction, with a mission of increasing awareness, efficiency and utility of additive manufacturing in the construction industry.

BILL: How do you describe 3D home printing?

ZACK: It’s concrete extruded with a giant robot. Our goal is to make these 3D printed homes look like homes, to normalize and commercialize the opportunity. The barrier is education and awareness. Since our first home came out last year, we get 25 to 30 requests per hour.

BILL: Wait. 25 to 30 requests per hour?

ZACK: Yes. The need is huge; this is an industry poised for rapid growth. The machines are getting faster and the transportation of these large machines to the job sites is getting faster as well.

BILL: (still shaking his head about the call volume) The extruded mix is just concrete?

ZACK: Yes, you can use store-bought concrete, and the industry is exploring additives and alternatives.

BILL: Can you describe how the windows, door, vents and other cutouts are made in your 3D process?

ZACK: Windows, doors and everything are pre-positioned with the CAD software and output to the extruding machine in the G-code file. As the concrete wall is built up, spaces are left and just the right tolerances for doors, windows and services.

BILL: And as for insulation?

ZACK: The exterior wall is two widths, 2-inches each with a gap for electrical conduit and plumbing, then filled with normal spray-foam insulation. For finish, we can leave the classic “ribbed” look of the 3D printing or can smooth the finish for a more stucco-like appearance. This is done with attachments for the 3D printing machine. We’re building on a slab, but our sequence of construction is a little different than a typical stick-built house. We lay the perimeter foundation with traditional methods, then the 3D printer arrives, and the walls go up. After that the slab is poured.

BILL: Let’s talk about the post-build technology. What is the role of the Raspberry Pi-based system? A home-grown smart home?

ZACK: We have partnered with Virginia Tech to design a system that measures the health of the home and sends the data to the homeowner and also back to Virginia Tech for analysis. Affordability is key to our model, so the low cost and efficiency of the Raspberry Pi compute module helps. As this is a new process, we need to capture the data that can inform constant improvement. Right now, what we are capturing focuses on indoor environment sensing — air quality, temperature, humidity, vibration, sounds, flame and many kinds of gases. It’s smart in that it’s learning and helping us improve.

BILL: What’s next in terms of projects, development and growth?

ZACK: We have 200 homes planned throughout the state of Virginia. The first two developments are in Pulaski, a town of roughly 8,000 in the Southwestern part of the state. This is Greenfield Development work, so design is important. We are mapping out the public space and making a true modern community.

BILL: Modern in what way?

ZACK: We’re tracking migration, in particular three migrations happening now — financial, climate and pandemic. Concurrent with this, work is changing, or more precisely, where we work is changing. For the first time we see a real shift away from being connected to major cities. More work can be done from home, creating what we call “Zoom communities.”

The Pulaski development is 30 to 50 units, and the process can be replicated elsewhere. What’s important is that we learn what the city, the major employers, and the local population need. We respond in terms of housing style, design, density and location. One thing we hear repeatedly is the need to reduce the commute, to get people out of their cars.

BILL: That has a positive effect on people, and the environment. It’s a good segue back to the impact of using concrete in the printing. All thing considered, is this a green technology?

ZACK: Great question. Current 3D house printing has two knocks against it. First, concrete is far from the most environmentally friendly building material. However, the process on-site creates 80 percent less waste than traditional frame construction. And the homes are efficient, we estimate they will be using 50 percent less energy over time. We are part of six different research initiatives at four universities studying alternatives to concrete. These include hempcrete, coal ash — of which there is an abundance in this part of Virginia — and recycled glass and plastics. We are confident the industry will see advancements. Our goal is a carbon negative home. Not neutral, but negative.

The other knock is that we are using automation to replace humans. But the interesting opportunity is that we need to get more people skilled in this technology to build the workforce that will be needed for 3D home printing to go mainstream. We’re creating a workforce development curriculum and offering it to all local colleges for free. The program will earn students a certificate in 3D concrete printing. Alquist will need to hire as well as others in the industry, so it will be important to have a trained and skilled workforce for the industry to grow. But it’s not just for us or for this industry; we feel it’s important to get more young people back into the trades.

Lower construction costs, less waste on-site, less energy consumption over time, increased housing affordability, and building a labor pool getting people back into a future-thinking industry. These are the opportunities of 3D printed home construction. Just like Gutenberg’s original printing press transformed the sharing of information, 3D printing could transform homebuilding. We are looking forward to the innovations to come.