The evolution of humankind is often measured in how structures have been built. From primitive shacks to giant skyscrapers, we can get a tangible sense of how things have changed. But, while at first glance that steel and concrete skyscraper may seem to be the apex of development, it turns out that it may actually look a lot more like that dirt shack.   

The old meets the new

Perhaps the most significant innovation in the construction industry over the last decade is the rise of 3D printing. While once a far-off concept, 3D-constructed buildings are now popping up (and quickly) all over the world. And while many of these structures are made with concrete, this isn’t the best material for the environment. Fortunately, a team of researchers at the University of Virginia may have found the solution: 3D-printed dirt. 

The project involved creating small, dome-shaped structures comprised of soil implanted with seeds. The team was able to find the right quantities of soil, water, and seeds and pump the concoction through the nozzle of a 3D printer to create a building.  

So, what can you do with dirt? Quite a bit, it turns out. 

“You can create pretty complex structures with it,” says Ji Ma, an assistant professor of materials science and engineering at UVA who led the research. “The strengths are not very high, but they’re certainly high enough for standing up and keeping their shape.”

Back to the past – with an eye on the future

Of course, creating structures with dirt isn’t anything new, as it has been a common building material for thousands of years. 

“One of the oldest construction materials is soil,” Ma says, referencing mud huts in Africa and adobe buildings in the American Southwest. “People were building structures from soil long before they were building with concrete.”

But clearly, 3D-printed dirt is new, and the implications are very exciting. It’s part of the bioconstruction trend, which is starting to build steam. In addition to sustainability, this type of construction focuses on respecting the environment and its inhabitants.  

And the team at UVA isn’t the only one working with 3D-printed natural materials. At Jerusalem Design Week, a group of designers unveiled several structures made from seeded soil built with a custom-made robot. Six weeks later, the plants developed a root system, and the walls had radishes growing out of them. 

“We wanted to create architecture that is made out of totally organic and local materials that you don’t need to transport materials from the other side of the world,” says Nof Nathansohn, an architect and researcher who worked on the project.

Cutting greenhouse emissions and a whole lot more

One of the main benefits of using dirt to build structures is that this eliminates the need to use materials like concrete and steel that leave a big carbon footprint. Homes made of soil that grow plants will actually be able to counter the harmful effect of typical buildings, as they could absorb more CO2 than they produce. 

But that’s not all this type of 3D printing can do, says Ehsan Baharlou, an assistant professor of architecture at UVA and a collaborator on the research project. He says that eventually, the method could be used to print buildings that utilize different soil and plant combinations that will be instrumental in keeping a structure standing firmly and well insulated.  

“We could change the material properties during fabrication in a way that you can have different kinds of functions,” Baharlou says. “You can have a green wall on one side and have structure on another side.”

While we’re probably still a long way from living in 3D-printed dirt homes, Ma says the technique could be used for something else almost immediately: landscape architecture. “Potentially, you have the ability to grow very different plant species that are normally adapted to different environments in the same place,” he says. “It has the potential for landscape architects to create menageries of different plant species.”

Creating structures from 3D-printed soil is only in its infancy, but the possibilities are very enticing. The description from the Jerusalem Design Week sums it up nicely:  

“Imagine a world in which the buildings around us can be 3D printed from living materials. A world in which buildings will germinate, bloom, wither, produce new kinds of material, and finally return to the same soil from which they emerged.”

Does this make you excited about the potential of 3D-printed dirt buildings?