3D printed houses – The future of construction? (Video)

The 1,200 square foot home features three bedrooms, two full bathrooms, and a covered porch. Yet it only took 28 hours to erect the concrete walls of the house – that’s because they are printed, which cuts the standard construction schedule by at least 4 weeks. Using automated computer technology and a proprietary concrete mix, Habitat for Humanity recently completed the first of many 3D-printed homes planned for Williamsburg, Virginia and elsewhere.

The new owner, April Stringfield, and her 13-year-old son are happy to know that the house will belong to them. Ms. Stringfield worked as a laundry facilities supervisor for 5 years at a local hotel, however, her income totals less than 80% of the area median income. Needless to say, becoming a homeowner seemed out of reach – until he was accepted for one of Habitat for Humanity’s 3D-printed homes. “My son and I are so grateful,” she said at the home‘s dedication. “I always wanted to be a landlord. It’s a dream come true.

Habitat for Humanity has built hundreds of thousands of affordable homes for people in need.

Grand opening of Habitat for Humanity’s 3D printed house on July 12, 2021.

3D printing is a relatively new technique in the construction industry, with the aim of improving economics and mitigating environmental impacts. It is an innovative space that combines the know-how of traditional construction with digital manufacturing. The elimination of formwork along with several other major benefits has great potential and has caught the attention of the construction industry.

Why 3D printing?

  • It saves contractors up to 15% per square foot on construction costs.
  • It provides better temperature retention, reducing heating and cooling costs for homeowners.
  • It is resistant to damage from tornadoes and hurricanes.

3D printed houses are already being built and sold to the general public.

How 3D printed houses are built

The concept of additive manufacturing – the more technical term for 3D printing – dates back to the 1980s, but has become much more popular over the past decade. 3D printing starts with a digital file of a house design. Large pivoting robotic arms produce fully functional houses as, layer by layer, they lay down materials to build the three-dimensional house, one layer at a time.

For Ms. Stringfield’s Habitat for Humanity home, Alquist used a proprietary concrete mix and an extrusion machine to print the exterior and interior walls, which were reinforced with steel during the printing process. Subsequently, the exterior walls were sealed with a clear or tinted coating that prevents moisture from transferring through the concrete. The contractor incorporated traditional cladding on the roof gables and used standard brickwork on the porch pillars.

Homeowners can choose a standard gray concrete color or choose from a range of attractive earth tones to give the home a custom look.

After Alquist finished printing the walls, the traditional builders built the roof, installed the plumbing and wiring, and installed the interior flooring and other finishes. Through the Williamsburg chapter of Habitat, contractors, subcontractors and other volunteers donated their time to complete the remaining portions of the house.

Life cycle analysis of 3D printed houses

The Life Cycle Assessment (LCA) framework is used to quantify the environmental loads of raw material extraction and manufacturing, as well as energy consumption during the construction and operation phases. Want the stats? A study conducted in the United Arab Emirates looked at the process of building a single-story 3D printed house to perform the benchmarking against traditional concrete construction.

The economics of the selected structural systems were studied using a life cycle cost analysis (LCCA), which mainly included construction costs and energy savings. An eco-efficiency analysis was used to aggregate LCA and ACLC results into a single framework to aid in decision-making in selecting the optimal and most eco-efficient alternative.

The results revealed that houses built using additive manufacturing and 3D printed materials were more environmentally friendly. The conventional construction method had higher impacts compared to the 3D printing method with a global warming potential of 1154.20 and 608.55 kg CO2 equivalent, a non-cancer toxicity of 675.10 and 11 .9 kg of 1,4-DCB and a water consumption of 233.35 and 183.95 m3, respectively. .

The 3D printed house has also proven to be an economically viable option, with a 78% reduction in overall investment costs compared to conventional construction methods. The combined environmental and economic results revealed that the overall process of the 3D printed house had higher eco-efficiency than the concrete construction. The main results of the sensitivity analysis revealed that up to 90% of the environmental impacts of 3D printing mortars can be mitigated with decreasing cement ratios.

Environmental impact of 3D printed houses

Alquist – the company behind Habitat for Humanity 3D printing – uses this technology to create designs while reducing the cost of housing and infrastructure in economically challenged and underserved communities. Every Alquist home is equipped with Virginia Tech’s exclusive Raspberry Pi monitoring system, which monitors the indoor environment, provides security and emergency management, optimizes energy consumption, and analyzes occupant comfort and usage. space.

Alquist also installs a 3D printer in the kitchen of every home it builds. The owner receives a downloadable computer file that will allow them to print knobs, light switch covers and other replaceable parts.

While 3D-printed homes are still rare, the Williamsburg home symbolized the potential for affordable homes that limit the use of natural resources like trees. Every new home built by Habitat for Humanity Peninsula and Greater Williamsburg is EarthCraft certified. EarthCraft is a voluntary green building program that serves as a model for healthy, comfortable homes and aims to both reduce utility bills and minimize environmental impacts.

Final Thoughts

The construction of each home built by Habitat for Humanity Peninsula and Greater Williamsburg is a cooperative effort between volunteers, home sponsors and home buyers. Participating families provide at least 300 hours of labor to build their own homes and those of other families, called labor equity. Habitat’s homeownership program resulted in monthly mortgage payments of no more than 30% of Ms. Stringfield’s income, including her property taxes and homeowners insurance.

3D printed homes are inherently resilient, cost effective and have a sturdy construction. They can help make housing more affordable and are likely to become another tool in toolkits to tackle homelessness and the effects of the climate crisis.

Do you want to know more about the possibilities of 3D printing? Check out these articles: hydraulic prototypes, electric vehicle parts and carbon fiber bikes.

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