A Chattanooga-based startup, Branch Technology, announced it has become the first company to successfully use 3-D printing to construct building walls to scale. The company used what it claims is the world’s largest freeform 3-D printer to create the walls with a process called Cellular Fabrication, or “C-Fab” for short.

During C-Fab, the 3-D printer solidifies a mixture of acrylonitrile butadiene styrene (ABS) plastic and carbon fiber in an open space, as opposed to typical 3-D printers, where thermoplastics are heated, cooled, and then layered to create a structure. The printer’s head is attached to a 12.5-foot robotic arm, which moves on a 33-foot rail. Using this system, Branch Technology can print a 3-D matrix 25-feet wide and 58-feet long. The reinforced matrix creates an internal support structure for layers of foam insulation, concrete and other conventional construction materials.

“We have an algorithm that can generate geometry and robotic code to create this matrix,” says Platt Boyd, CEO of Branch Technology. “That open matrix is very lightweight. We fit them together like big Lego blocks on site, [and] then you apply construction materials on site to become a wall assembly in the field.”

What makes Branch Technology’s machine a game-changer is that it potentially eliminates shape limits.

“When geometry is not an issue, you can do almost anything,” Boyd said. “If an architect can send us an original design file we can fabricate that.”

In addition to design freedom, the new technology provides added efficiency to traditional construction methods, as well as increased strength and reduced weight to overall structures.

“Modern buildings are always systems that come together to form a composite assembly,” Boyd says. “We’re saying: how little can we 3-D print and allow these other materials to become the strength of the wall assembly?”

Boyd says the next step in the development of the technology is primarily focused on wall construction right now, but will eventually be able to make roofs as well. However, his company may be first to do it. He says the first firm who uses the company’s C-Fab Technology to construct the first completely 3-D printed house will win its $10,000 design competition. The contest begins in September, and entrants must supply plans to build a house between 1,200 and 1,400 square feet.