3D Printed Homes
The Third Dimension
2023-01-11Exciting as it was to hold an object that was made by 3D printing technologies, it was not close to the excitement of realizing that there are people actually living in buildings created by 3D printing technologies.
Using basically the same technology, these buildings are created with the help of very large printers and processing materials that are suitable for a building structure, usually concrete.
The first building that was built using 3D technologies was the canal house in Amsterdam, by DUS Architects. They used hotmelt: a bioplastic mix that is about 75% plant oil, to create units that were assembled together. The canal house was built in 2014, was available for visitors and then was dismantled in 2016.
A Chinese 3D construction company named WinSun also printed a house as early as 2014 and then moved on to printing an apartment building in 2015. They used a mixture of ground construction and industrial waste, such as glass and tailings, around a base of quick-drying cement mixed with a special hardening agent. Since then, the company has built various projects such as a government office building, green wall, sound barrier, a museum, and more.
A company named ICON claimed the first 3D printed permitted home. For their 3D printing construction projects, ICON uses Lavacrete, a proprietary Portland Cement-based mix, which they claim can withstand extreme weather and can be sourced from anywhere in the world. ICON also partnered with New Story to build an affordable 3D printed neighborhood in Mexico, that claimed to go through an earthquake with no damage, and homes in Austin, TX, which are built for the homeless that survived the snowstorm during winter 2021.
Dubai was the one to claim the first 3D printed office that became fully operational in 2016. The material used was a special mixture of cement.
3D Printing
3D printing has been an emerging trend for quite some time for many varying applications and has yet to become mainstream. However, in recent years, with the help of software, advanced materials, lower costs, and capital, there are some indications of a brighter future.
As with other applications, manufacturers in the construction space are emerging or joining this trend of using 3D printing technologies. Some manufacturers print the units in factories and then ship the completed units to the building’s site, which is a similar process to modular homes, and some transfer the large printers to the construction site to perform the actual printing on-site.
3D printed homes have characteristics that are different from traditional construction:
- The time of construction is reduced significantly. Many buildings can be printed in a matter of a few weeks or even days. Some manufacturers promise to print small houses in less than 24 hours. Note that the printers only print the structure of the buildings, the foundations, and walls. For the whole building to be complete, the rest should be assembled: roof, doors, windows, plumbing, insulation, and more.
- Manufacturers claim that there is no waste involved in the 3D printing construction because only the materials needed for the structure are being used and there are no excess materials left.
- The reduced time and materials needed for 3D printed construction reduces the cost of a 3D printed structure vs. standard construction or other prefabricated homes.
What About (True) Sustainability?
One aspect that is still not clear is how sustainable this type of construction is. In traditional construction, we can rely on building codes, and at times, third-party certifications that evaluate the durability and safety of the building, the materials used, the manufacturers, and any professionals involved. Since 3D printed buildings are relatively a new practice, code officials are not experienced and may not have the technical expertise to evaluate these buildings. Furthermore, third-party certifications are not yet abundant.
In 2017, UL started researching and consulting with experts to develop UL 3401. The standard is set to evaluate 3D printed construction with regards to quality, strength, effectiveness, fire resistance, durability, and level of safety. The evaluation covers properties such as mechanical properties, fire performance, vapor, air and water barriers, thermal insulation, indoor air quality, durability, integrity, and performance before and after environmental exposure conditions.
Are 3D homes safe?
Mighty Buildings is the first company to have earned UL 3401 certification for 3D-printed buildings. This 3D printed house company print the buildings off-site with a thermoset composite and once complete, they ship them to the building site. The UL 3401 certification evaluates the durability and resilience of the structure as well as environmental aspects such as indoor air quality and insulation. Yet, thermoset polymer, which is the material processed in the printing process, cannot be remelted after it solidifies. Its material properties are fundamentally altered as it cures, which makes it very difficult to recycle. It is generally strong and durable but is it environmentally friendly? Not sure.
SQ4D is another company that prints 3D homes. They declare that their construction is safe, strong, and environmentally friendly. But without a third-party certification, we can either take their word that the structure is sustainable or not.
TECLA in Italy tried to tackle the material used for the 3D printing. With the technology of WASP, they printed three small habitable units and used reusable and recyclable materials, sourced from local soil and that are carbon-neutral. They state that the material is adaptable to any climate and context, but that will only be determined in the future, once it’s completed, occupied, and has been performing over time.
In the meantime, the United Kingdom Green Building Council (UKGBC) chose to include the project among sixteen others, in the Build Better Now virtual pavilion during COP26 in Glasgow.
Another 3D printed home that used the WASP technology, is a house called GAIA. The house was printed on-site with a natural mud mixture made from soil taken from the surrounding site, as well as waste materials from rice production such as chopped straw and rice husks. The company claims that it is a high-performing structure in terms of energy, with almost no environmental impact, it is biodegradable and will turn back to soil if not maintained. This sounds very promising in terms of the environment but raises questions about its resilience.
Similarly, the University of Maine and Oak Ridge National Laboratory designed and manufactured the BioHome3D from a 100% bio-based home. It is printed with wood flour or fine sawdust mixed with a binder made from corn. Unlike other 3D printed homes, in this design the roof is printed instead of the front of the house which is also made of wood.
Using renewable and locally sourced wood fiber feedstock reduces the structure's environmental impact but raises questions about it's climate resilience. If all the home's elements are made of wood, the home is 100% recyclable but would it be fire retardant? Would it withstand a fire? Especially when a conventional gas stove installed within. The sloping curve of the design can help withstand strong winds but would the 100% wood insulation manage moisture well? Would it withstand water damage in case of a flood?
We reiterate that eco-friendly homes are crucial, but if they are not climate resilient, they won't sustain in most climates in the U.S.
Final Thoughts
- It seems that 3D printing construction is the fastest construction currently available.
- In most cases, only the walls are printed, while the roof, windows, doors, and finishes need to be completed on-site or pre manufactured using different methods of construction. As with prefab houses, connecting the elements on site is critical to the structure’s resilience.
- The material used for printing is a significant factor in determining whether or not the structure is sustainable (resilient and green). The majority of solutions today use concrete, which makes the house more durable and resilient, but its environmental friendliness is in question since concrete is well known for its embedded carbon.
- Once manufacturers apply for third-party certifications, it will be easier to determine the structure’s true sustainability.
KEEP COOL. BUILD RESILIENCE. EAMPACT.
