Is Construction Set for a 3D Revolution?

In recent years, the U.S. housing supply shortage has dramatically worsened—from a deficit of 2.5 million units in 2018 to a deficit of nearly twice that number, 4.5 million units, in 2022, according to a “Perspectives” piece by Freddie Mac’s Chief Economist Sam Khater.

The shortfall was created, in part, by supply chain interruptions during the COVID-19 pandemic, lack of skilled labor, and substantial reduction in the building of entry-level homes. While such challenges have been burdensome, they have also been the source of ingenuity in efforts to address the U.S. housing shortage. Forward-thinking construction companies have pumped resources into developing cutting-edge 3D printing technologies, turning small-scale 3D printing into large-scale construction in the residential and commercial marketplace.

The emergence of 3D printing construction is being touted as faster, more sustainable, and a less expensive means of building than traditional “sticks and bricks.” 3D printing industry proponents have stepped up, pushing the boundaries of what is possible in both residential and commercial construction by using creativity and technological advancements. No longer is 3D printing construction a vision of the future; it is a reality, with a near-complete 100-single-family residential subdivision in Texas, and a 2026 completion date for the first 3D printed hotel in the U.S.

3D Construction Process

Although materials and tools have become more sophisticated over time, basic means and methods of building a traditional single-family “stick and brick” residence are largely the same as 100 years ago. On average, traditional building methods include at least six layers of material: wood or metal structural framing; insulation; exterior sheathing, such as plywood or OSB; weather-resistant barrier; exterior siding; and interior drywall.

Instead of constructing six different layers of material, 3D construction “prints” a structure’s walls from a computerized three-dimensional model by successively stacking thin layers of a single proprietary cement-based mate[1]rial, which is heated during a thermal extraction process, squeezed through a nozzle, and then solidified by a concrete dryer before the process repeats to render its digital design (as described in ISO/ASTM 52939:2023, Additive manufacturing for construction — Qualification principles — Structural and infrastructure elements). Once the structure’s walls are printed, traditional construction techniques still come into play to install the roof, plumbing, electrical, HVAC systems, windows, doors, appliances, and finishes.

To accomplish this new age construction, builders rely on the advancement of two primary 3D printing machines: a gantry-style printer and a robotic arm printer. Both 3D printing models are limited due to lot size and maximum printable area, which has resulted in 3D construction primarily focusing its efforts on building single-story structures. Some companies are working to create new machinery capable of printing two-story buildings, which, if successful, will open the door even wider for the utilization of 3D printing.

Scalability

In the U.S., on average it takes 7.6 months and between 11 to 30 subcontractors to build a traditional wood framed single-family residence, according to industry surveys. 3D printing technologies significantly reduce both the time and labor required. The entire exterior envelope and interior wall structure of a 1,900-square-foot structure can be printed in just 48 hours, spread over eight days, according to 3D homebuilder SQ4D. During that time, only two to four workers are needed on-site to monitor the machines and feed in materials, potentially reducing labor costs by as much as 80%, according to ZDNet, citing All3DP figures.

Because 3D printing is achieved by stacking layers of the same material on top of one another to create both the structure and weather barrier system, precision is critical. Builders cannot simply go to their local construction supply store and pick up a bag of concrete and print. Rather, 3D printing materials are proprietarily made, often on-site, requiring skilled workers to monitor and adjust the material mixture to accommodate environmental conditions.

The material must be fluid enough to extrude through the printing nozzle but strong enough to hold shape. Materials require enough time to cure between layers, but not too long where the cement-based product dries out, preventing the layers from properly adhering. Higher temperatures can cure the material faster, but may limit its strength, while lower temperatures mean slower curing. Areas of the U.S. with comparatively stable daily temperatures, such as Texas and Florida, have had more success with curing and strength testing.

With technology and standard practices rapidly evolving, builders jumping into the 3D printing construction industry are creating internal training programs for employees to learn how to monitor the 3D printers and produce printing material mixtures. Increased efforts to standardize materials and methods while working to evolve building codes specific to 3D printing construction will play a key role in the ongoing expansion of this technology.

Sustainability

Energy efficiency offered by 3D printing has also ignited the construction industry’s efforts to reduce carbon emissions, further spurring consumer interest. Builders aiming to minimize their carbon footprint are pushing to develop their own ranges of 3D low carbon mortar materials through the use of additional binding agents or reinforcements like graphene, as described in a recent Construction Dive brief. Localization of the 3D printing process has also resulted in lower transportation costs and emissions, according to SQ4D. A recent case study, performed by MIT Concrete Sustainability Hub, estimates that 3D printing has the potential to reduce carbon emissions in construction by 2% to 9% over the life of a structure.

Builders are also tackling the environmental challenge of water usage required to print with a cement-based material by recognizing that states like Nevada impose strict water conservation regulations requiring specialized concrete mixes designed for low-water content. With the ability to adjust 3D printable mortars, builders are working to conform to these requirements while still meeting the necessary strength and extrudability metrics needed to print.

Additional benefits of 3D printing are also being touted, such as higher fire ratings than wood-framed structures, which could potentially encourage insurers to offer coverage in areas impacted by fire losses. Such structures are also far less likely to experience mold or termite issues. If that was not enough, efficiency of time and low-labor requirements are encouraging 3D printing construction to be considered as an effective way to provide shelter in disaster-stricken areas, as noted by Printerra, a Canadian construction company specializing in 3D concrete printing. Construction Costs When budgeting a construction project, the two most expensive line items are labor, estimated at averaging 40% of the overall cost; and materials, estimated at between 40-50%. 3D printing reduces the labor hours needed and minimizes material expenses, resulting in overall cost savings. Material losses due to damage or theft account for 10% of the materials budget in traditional construction. With 3D printing, a computer program maps out the progression of construction and calculates the exact amount of material needed, reducing up to 95% of material waste and saving, on average, an estimated $10,000 per project, according to All3DP. 3D printing also replaces the volume of materials needed such as lumber, weatherproofing, siding, and drywall, minimizing or potentially eliminating delays or budget overages due to supply chain issues and rising lumber prices.

Other Considerations

As with any new technology, the emergence of 3D construction also brings new legal and regulatory questions that must be answered. In 2021, the International Code Council introduced Appendix AW to the International Residential Code to implement new standards for the design, construction, and inspection of 3D printed construction. This appendix also incorporates Underwriters Laboratories’ UL 3401 standards, which provide additional guidance on requirements for mechanical strength, fire resistance, non-combustibility, thermal insulation, sound insulation, and indoor air quality. However, the implementation and application of these standards are sure to create disputes when the construction is called in question.

Construction contracts are also evolving to address 3D printing issues, such as how often the concrete material should be tested to ensure appropriate strength and structural integrity, or how the impact of delays in construction will be addressed due to any equipment failures. Should litigation arise, experts with 3D printing qualifications will be critical. In cases where the print itself may be at issue, the primary cause or con[1]tributing factors related to potential defects may be challenging to evaluate, as well as any remediation and repairs.

3D Printing in the Real World

In late 2022, Lennar, a prominent U.S. homebuilder, announced that it was partnering with ICON, an Austin, Texas-based 3D construction company, to construct a housing development comprised of 100 3D printed homes in the master-planned community of Wolf Ranch by Hillwood Communities, in Georgetown, Texas. Houses in the Wolf Ranch development range from 1,574 to 2,112 square feet. Construction of the Wolf Ranch project began in early 2023 and is almost complete, making it the first 3D printed mass subdivision of its kind in the U.S.

On Sept. 12, 2024, ICON also announced its intention to construct the world’s first 3D printed hotel and residences at El Cosmica, a 21-acre nomadic hotel and campground in Marfa, Texas. Designed to fit into the desert landscape, 3D printing allows for soft shapes and curved surfaces that are difficult and costly to create using traditional building techniques. This ground-breaking hotel will feature guest accommodations, a pool, bathhouse, restaurant, and even private residences and is expected to be completed in 2026. The commercial sector also has an eye on utilizing 3D printing to add on to big-box-store floorplans or warehouses. In September 2024, 3D construction company Alquist 3D completed construction on an 8,000-square-foot addition to a Walmart store in Athens, Tennessee. The addition is one of the largest free-standing 3D printed commercial concrete structures in the U.S.

With housing and labor shortages on the rise and growing material costs due to supply chain interruptions, faster and more cost-effective means of construction are needed. As companies race to set new standards for construction in the U.S. and across the globe, the evolution of new technologies like 3D construction are already creating opportunities to address these issues. Whether home buyers fully embrace the strikingly futuristic look of 3D printed homes remains to be seen. However, with the appeal of lower construction costs, energy efficiency, and decreased construction time, 3D printed homes are an exciting and innovative new alternative in residential and commercial construction.

The authors offer a special thank you for the contributions of Nicole Johnson, partner in Tarle Law’s Dallas office.