Up to now, construction has relied on rigid techniques that usually create big amounts of waste. By adding material instead of shaping it via extractive processes (cutting, sanding, readapting), 3D-printing allows for complex designs, is faster, and creates 90% less waste.

Thanks to new extra-large 3D printers, it’s now possible to print a house with a machine that extrudes a material – usually concrete/cement or a polymer, but more lately even earth – in an entirely additive process so there is exponentially less waste in construction.

Mighty Buildings can print a home in just 24 hours in their Oakland, CA factory using a thermoset polymer composite that is cured with a UV light (on the printer head). The process is fast enough for the material to support its own weight allowing for organic shapes but slow enough that there is cohesion between layers.

The company stayed in stealth mode while working through the regulatory challenges of such a novel technology. “The reality is the building codes are written in blood,” explains Mighty Building’s co-founder Sam Ruben, “and we want to make sure that we’re actually getting ahead of that because we don’t want 3D printing to get in the codes only when something goes wrong. So that’s why we’ve moved iteratively to make it as easy as possible for building officials to say yes and allow us to begin delivering units while we continue to demonstrate and build out our portfolio.”

To launch 3D printed homes with their iterative approach they began selling units with just a printed curved wall that were sized to be dropped into backyards as ADUs (Accessory Dwelling Units). And now, they have begun selling kit homes so anyone can customize their own printed home. “The idea here is instead of delivering fully finished modules, we actually deliver a flat-pack panel system similar to a Sears Kit Home from the ‘20s and ‘30s, but updated for the 21st century.” Ruben calls it a “SIPS panel on steroids” because unlike a SIPS panel it can be used as an exterior cladding with a finish that acts as an air, water, vapor, and fire barrier.

Mighty Buildings hasn’t tried to print everything and, instead, they are taking cues from the shipbuilding industry by buying prefab sections (like bathrooms) so they can plug and play to quickly finish units on a larger scale. They also hope others will be interested in collaborating and setting up their own Mighty factories to print more locally and rapidly.

It’s another reason they’ve worked with the largest standards-making bodies to help develop their new regulations for 3D printed construction. “We helped develop the world’s first standard for 3D printed construction (UL 3401) which has been used as a basis for appendix AW in the 2021 international residential code update that means that jurisdictions that use the IRC can plug it into their local codes”.