3D printing technology is having a revolutionary impact on enterprises around the world. One of the most exciting applications of 3D printing technology is in the construction industry. 3D printing is now being used to construct entire homes, office buildings, and other structures. 3D-printed buildings can span thousands of square feet and multiple stories, and they can be made with lower costs and less waste than traditionally constructed buildings. This article will present comprehensive information on 3D-printed buildings including overview of the technology, engineering considerations, and related resources.

3D Printing Defined
3D printing employs large-scale machinery into which an engineer inputs floor plans and building designs. Concrete and other building materials are then fed into the machine. An extendable arm, or nozzle, then applies the mix of building materials in thin layers, guided by software. The entirety of the building or structure is then made according to the engineer’s specifications, one layer at a time. While methods vary, many 3D printing techniques require very little additional assembly from workers.

The Benefits of 3D Printing
3D-printed buildings offer a number of benefits:
• 3D printing ensures that construction materials are used exactly; there is no waste, as the printer can precisely administer building materials according to the blueprint.
• Both because there is so little material waste and because fewer human workers are needed to assemble the structure, 3D-printed buildings can be highly cost-effective. Some builders have been able to make homes for less than $4,000, pointing toward potential options for low-cost housing.
• Less material waste and shorter construction times also mean that 3D-printed buildings have a smaller environmental impact than more traditionally constructed buildings.

3D Printing Technologies
There are a number of specific technologies that can be used to produce 3D-printed materials and concepts. Fused filament fabrication, or FFF, is a 3D printing method that employs a continuous filament of thermoplastic material. It is sometimes referred to as fused deposition modeling (FDM).
An alternative 3D printing method is stereolithography, which builds models, structures, and patterns layer by layer through a photochemical process that uses light to turn a liquid resin into hardened plastic.

On-Demand Customization
To fully understand the different applications of 3D printing, it’s important to note just how easy it is for engineers to tweak, adjust, or modify a model simply using software; the 3D printing technology can then reflect those changes with precision. This allows for on-demand customization, as production can be adapted with very little lead time or added inefficiency.

3D-Printed Buildings at a Glance
The construction and engineering applications for 3D printing are diverse. 3D printing has been used to make buildings of all different kinds and varying levels of complexity, from single-family homes to multistory office buildings to bridges.

Types of Materials
While 3D-printed buildings can be made from a number of different components, the most common method involves a material mix that consists of concrete, fiber, sand, and geopolymers. These different raw materials are thoroughly mixed in a large “hopper,” at which point they can be fed into the extrusion apparatus and layered into the correct shapes and patterns. There have also been instances of homes 3D printed from fully biodegradable materials, including mud, soil, straw, and rice husks.

Parts of the Building
Typically, when constructing a building or structure, only the frame and walls can be made with 3D printing. Other elements of the home, such as windows and doors, the plumbing system, and the electrical system, must be manually installed. However, in recent years, 3D printing technology has advanced to the point that even some plumbing and electrical fixtures can be built in and already integrated into the home.

Recent Building
Recently, the 3D-printed building industry has seen some significant milestones. The biggest 3D-printed building in the world was erected in Dubai at the beginning of 2020; an administrative office building, it spans more than 6,900 square feet. Meanwhile, Russian company Apis Cor has innovated new methods for building 3D-printed single-family homes in under 24 hours, even in extreme weather conditions.

Challenges to 3D-Printed Buildings
While 3D printing provides civil engineers with a number of opportunities, it also comes with challenges. Specifically, engineers may face hurdles related to structural inhabitability, material integrity, and equipment limitations.

Structural Inhabitability
One longstanding concern with 3D-printed buildings is that 3D printing technology is not, in and of itself, enough to make buildings habitable. While 3D printers can make walls and frames, they have historically come up short in terms of quality-of-life essentials such as running water and electricity, to say nothing of HVAC work. In recent years, 3D printing technology has made some strides forward, with new methods being developed for printing some basic electrical and plumbing components. Additionally, engineers can design homes in such a way that the basic 3D-printed structures are easily retrofitted with pipes, wiring, and ducts.

Material Integrity
An even more serious drawback is that 3D-printed structures, when tested, usually turn out to be less strong and sturdy than more conventional buildings. This is because the materials used in 3D-printed buildings tend to break down and lose some of their structural integrity over time. Engineers have long been working on new material methods that can withstand rigorous testing and comply with all pertinent building safety codes. There have already been many successes in this regard, including through refining existing concrete and polymer mixes and by incorporating biodegradable materials.

Equipment Limitations
It should also be noted that, while 3D printers have come a long way, the equipment itself still has limitations. While one of the great promises of 3D printers is that they can do the work of many machines at once, the reality is that a lot of 3D printers are restricted in their functionality. This means that they can make large structures, but not necessarily complex or detailed ones.

One of the primary goals in the 3D printing industry today is to innovate new construction methods that are efficient and low-cost, but that also enable a wider range of precision and functionality. Companies such as WinSun, in China, have gained attention for their amazing productivity (including the capability to build 10 homes in a day), though it remains to be seen how durable these buildings truly are.

The Future of 3D-Printed Buildings
The construction industry continues to face significant problems; specifically, traditional construction methods can often be highly wasteful, time consuming, expensive, and hazardous to the environment. Through the precision, speed, and reliability of 3D printing, civil engineers have a number of opportunities to correct these problems and potentially make it simpler and more affordable than ever to design and build habitable structures.
When it comes to the future of 3D buildings, the sky may not be the limit: both NASA and the European Space Agency have begun brainstorming ways to use 3D building technology to create habitable buildings in space, or even Martian colonies. Given the innovations of the past decade, the possibilities for this cutting-edge technology are boundless.

For Further Reading:
• Interesting Engineering, “Your Future Home Will Probably Be 3D Printed: How 3D Printing Is Changing the Construction Industry.” Learn some of the trends that are shaping 3D printing and increasing its viability in the construction industry.
• ExplainThatStuff, “3D Printers.” Find out how basic 3D printing technology functions.
• FormLabs, “Guide to Stereolithography (SLA) 3D Printing in 2020.” A comprehensive guide to how SLA printing technology works.