A 79,000-square-foot former coffee warehouse is home to Mighty Buildings’ automated production line, which includes a large-scale additive manufacturing printer and one automated robotic cell. It takes 24 hours or less to print and put together the composite components required to build a 350-square-foot ADU. The process requires 95% fewer labor hours than traditional building and generates just one-tenth of the waste, according to Mighty Buildings’ co-founder and COO Alexey Dubov.

The 3D printing system includes a basic gantry, a moving frame and a unique, rotatable printing head mounted with ultraviolet (UV) modules. For the construction material, Mighty Buildings developed a proprietary, pre-mixed material of mineral and resin called Light Stone. This thermoset composite is in the same class of materials as Corian’s solid surface materials but has a Class A flame spread rating instead of Class B.

“We can turn the material into a gel that allows us to extrude it into pretty much any shape,” Ruben explains. “Because of the UV curing that we’ve introduced, it cures quickly enough that it can support its own weight, but not so quickly that we don’t get full cohesion between the layers.” Before printing a structure, Mighty Buildings uses simulation software from MSC Software to identify potential production bottlenecks or design issues.

To date, Mighty Buildings has focused on printing the composite components of its first modular product line, Mighty Mods. The available buildings include one 350-square-foot model and two 700-square-foot buildings; all come equipped with a full bathroom and a kitchen area and can be customized. The Mighty Mods can be used for a variety of purposes, including housing for extended family, space for a home office or an income-generating rental property. Mighty Buildings prints the equipped Mighty Mods in the factory, trucks them to the building site and then lifts them into place using cranes. (You can take a virtual tour at tour.mightybuildings.com.)

The buildings’ walls, supported by a steel frame, consist of two panels, between eight and 14 millimeters thick, which are separated by a six-inch cavity filled with a high R-value foam insulation. Exterior walls currently feature traditional building cladding, but Mighty Buildings expects its Light Stone material will achieve a minimum one-hour fire rating, which means it could serve as the ADU’s exterior walls.

The company plans to introduce a fiber-reinforced material sometime in 2021; the addition of the fibers into the printed material will be automated.  “With the new fiber reinforcement, it’s going to allow us to eliminate any need for steel because the performance of the reinforced material is actually better than reinforced concrete walls, with four times less weight and four times more insulation,” says Ruben.