The 2016 construction of Dubai’s Office of the Future signaled that 3D printing in construction was ready for its close-up. The 2,691-square-foot building uses energy-efficient HVAC systems, responsive LED lighting, and solar shading to reduce power consumption, and it took a team of 18 people just 17 days to complete using a 20-by-40-by-120-foot 3D printer. After cementing its place as a product-prototyping technology, 3D printing has branched out into a whole new dimension.
But for the construction industry, 3D printing is as much an urgent need as it is a flashy novelty. Construction is responsible (PDF) for 23% of air pollution, 40% of drinking-water pollution, and 50% of landfill—and that needs to change. As the software and machinery improve, architects and construction firms are increasingly turning to 3D printing to realize complex shapes; build in dangerous or remote areas; and save time, money, and materials. The age of 3D printing in construction is here—and as barriers fall away, it will become key to sustainable construction in the future.
3D printing has been around a surprisingly long time, existing in practice since 1971. After a couple of decades of development in the industrial world, a variety of 3D-printing techniques have emerged—though only a few are suited to construction:
Extrusion is the process of heating a material to a near-melting point, forcing it through a small aperture, and then applying it to a surface where it starts to solidify into a shape dictated by the angle and force of the extrusion. Extrusion was behind the consumer 3D-printing craze because it suits lightweight materials such as polymers or carbon fiber.
Since its origins, extrusion technology has expanded into everything from metals to biological material. It’s the cheapest form of 3D printing, and in construction, it mostly applies to small, lightweight components.
Also called binder jetting, bonding can be used with an extruder or a process that's more like the way an inkjet printer applies ink to the page: “spraying” it directly, albeit in a much more precise and targeted way.
The 3D-print head deposits a thin layer of bonding agent onto the previous layer along with the input material, giving the next layer of material and the overall structure more strength and stability. Bonding’s suitability for materials such as metal powders, ceramic metal compounds, and sand makes it ideal for construction.
Additive welding is the newest technique for working with tough materials such as metals.
Rather than heating material and forcing it through an extruder or shooting it inkjet-style from a nozzle, additive welding uses an energy source—anything from a laser beam to a traditional arc welding torch—to melt the material into powders or small strips or wires, which are laid onto the previous layer, cooling and setting rapidly into a predetermined shape.
Of the myriad components that go into a construction project, many of them (metal, concrete, rubber, plastics) can be 3D printed. Innovations already exist to make them easy to work with, such as programs designed to print a specified component (a wall, an aircraft wing, et cetera) with all the wires, pipes, seals, framing, and other materials and pieces already present, all extruded in the same multi-material process.
Crucially for construction, concrete is a viable candidate for 3D printing because 3D printing concrete uses the same ingredients (sand, water, aggregates) as a traditional process. But instead of dumping everything in a mixer and adding sand or water on the fly, the mix and consistency have to be correct in the beginning so they don't clog the extruder or applicator.
Today a 3D-printed house or building is managed by deploying a printer onsite. For the largest projects, that means a full-size gantry that can move the extruder head anywhere around the building it needs to go.
For instances where that's not feasible, the building blocks of a construction project can be printed and then shipped to the site—a process that is rapidly improving. One Oakland, CA, business is making 3D-printed bricks (called “modular building components”). Using nothing more than clay and sand, the Cool Brick from Emerging Objects can cool a room and even stabilize the entire building structure during an earthquake.
For construction firms and buyers willing to jump in, 3D-printed construction materials offer a host of advantages that, when scaled industry-wide, could upend the built environment.
The construction industry as a whole is expected to churn out 2.2 billion tons of waste by 2025—making the environmental benefits of 3D printing crucial.
A lot of items are made by cutting or forming things out of bigger things, subtracting material. As one of the biggest industries on earth, construction contributes a lot of those material off-cuts. Building a structure from a 3D printer means provisioning only the input material you need and not a single gram more.
The construction industry is responsible for 39% of all energy-related carbon dioxide emissions. By eliminating the need to produce and ship energy-intensive materials, 3D printing can make construction greener. One exciting application is potentially sending a 3D printer to space and building a habitat on Mars from the very dirt it landed on.
Closer to home, builders can use locally available, naturally occurring materials. Upsides include reducing toxic materials on jobsites and minimizing the need to transport materials to a site and remove waste (or remove demolition waste from existing structures).
Additively manufactured buildings incur cost savings throughout the process: You don’t need to buy more material than you need. You don’t need to ship or truck materials in. You don’t need to take leftover or unused material away. You don’t need unskilled labor for carting, stacking, barrowing, or preparing bricks or lumber frames.
If environmental conditions are favorable, a 3D printer can run 24 hours a day, seven days a week, with no more attention needed than restocking input material and maintaining a power source.
It’s a common frustration: An architect creates an innovative design, but materials, building practices, or physics dull the sharp edges of that unique vision, resulting in a more traditional final result.
By contrast, additive manufacturing means the weight distribution or spatial needs of a way-out design are built one layer at a time, supporting their own weight or footprint as they're manufactured. Traditional methods or tools don't have to dictate the design any longer.
Deaths in the construction industry rose throughout the 2010s, reaching a 12-year high in 2019. Transportation accidents, falls, exposure to harmful substances, and fires are behind most of these tragedies, but a 3D-printed built environment could do away with virtually all of these hazards.
Translating a 3D representation of a structure directly to the machine building it (rather than to humans reading plans, which can lead to translation errors and conflicting information) means more precision and automation, taking more people out of harm's way. Damage to and injury from stored materials can become a thing of the past when there’s no onsite material to store, move, and manage.
Despite these benefits, 3D printers are still scarce on building sites. When smartphone networks became ubiquitous, landline infrastructure was replaced on a wholesale basis. Why hasn’t the same happened for 3D printing in construction? The reality is that although the theory is sound, very real bottlenecks limit widespread adoption.
The supply chain for lumber, metal frames, window glass, plumbing, and energy fixtures is deeply entrenched in the economy—from the global supply of wood or steel down to local suppliers and builders—and the price points are accounted for from the inception of every new project.
Despite the long-term advantages in speed and costs, 3D printing still has a high up-front cost, and it’s not necessarily one that can be passed onto the buyer; part of the appeal for the whole movement is an assumed cost saving.
Despite a million construction firms in the world, very few have experience with 3D printing. The field needs software engineers and materials scientists to work with builders, and growth in the area—training more of these specialists in colleges or on the job—has to outstrip more general growth in construction for the necessary experts to stay ahead of the demand.
Creating buildings is one of the most highly regulated areas of the economy. Although the laws apply to any dwelling regardless of manufacture, they were created for traditional construction based on a century of mass industrialization, and building codes don’t directly translate when new manufacturing pathways such as 3D printing are used.
That makes the practice of 3D printing a building (rather than the end product itself) a very unregulated area, something both owners and investors remain wary of until regulations can catch up to the technology.
Bringing together the old and the new, Dutch technology firm MX3D built a stainless-steel 3D printed footbridge across the 670-year-old Amsterdam canal in 2015. Traditionally, 3D-printed structures were constrained by the size of the printer, but MX3D used thin molten-wire inputs to create the 40-foot bridge in a single piece, floating it into the canal system for transport and fixing it in place.
Today, the footbridge is more than just a bridge: Coupled with real-time data on strain, vibration, and displacement taken from foot traffic and fed into Amsterdam's smart infrastructure grid, it’s a critical sensor in the effort to measure the city's lifeblood. It's also a conversation starter: a way of bringing 3D printing to everyday lives. As MX3D cofounder Tim Geurtjens said at the time; “It’s not just for commercial sake; it’s also to make what you want to make because it’s possible.”
Among the players printing houses and office buildings, it’s been a race for superlatives: the biggest, fastest, cheapest, and so on.
Back in 2015, however, Chinese company Winsun reached the “biggest” milestone first with its 3D-printed six-story apartment building and biggest 3D-printed house. Today, the firm is pioneering environmentally friendly materials such as fiber-reinforced plastic, glass fiber–reinforced gypsum, and the intriguingly named Crazy Magic Stone.
Of course, 3D printing is about more than the flashy projects that the media flocks to. In 2017, France’s YRYS concept home used injection molding to press layers of rapidly setting 3D-printed concrete into perforated walls and support columns to hold the upper story aloft, changing the game by creating building components that are lightweight but strong.
3D-printing technology can be used to benefit nature. The practice of scuttling decommissioned navy and merchant ships provides havens for undersea life to flourish because their many nooks and crannies provide diverse habitats. In the same spirit, XtreeE (the company behind the YRYS House concept home) created a 3D-printed artificial reef in 2017 for a marine national park off the southern coast of France.
The irregular tunnels in the structure encouraged the growth of fish, mollusks, corals, and algae populations, which started to decline after the loss of habitats in the 1970s from city wastewater. Today, healthy sea life has returned to the region.
Taking cues from biology, Tennessee-based Branch Technology is creating some of the biggest structures ever produced using 3D printing.
The company’s process takes any software-based 3D architecture model and changes it into a freeform lattice structure that can be 3D printed to act as formwork for traditional materials. In 2018, the company produced the largest 3D-printed object in history, a 42-foot-long bandshell for a Nashville entertainment precinct.
The design mimics biology is in the way living tissue is formed and grown at a cellular level. The 3D-printed “shell” is the outer superstructure; the strength and purpose of the structure is then fortified with traditional construction materials (analogous to the blood, water, plasma, and so forth within cells).
It will take a long time to destabilize and ultimately depose incumbent building practices and the industry players insisting on them. Like similar movements, 3D-printed construction isn’t a technology problem; it verges into political and economic areas.
But at some point, there will be a magic moment when 3D-printed buildings become cheaper than traditional construction methods, thanks to a safer, faster process with reduced environmental impact.
The construction industry is watching for that point very carefully, and as soon as it’s reached, the industry will start to shift rapidly, with businesses, organizations, and governments racing to stay ahead of the curve.
This article has been updated. It originally published in August 2018. Jeff Link contributed to this article.
After growing up knowing he wanted to change the world, Drew Turney realized it was easier to write about other people changing it instead. He writes about technology, cinema, science, books, and more.
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