Robot builder could 'print' houses

A robot for "printing" houses is to be trialled by the construction industry. It takes instructions directly from an architect's computerised drawings and then squirts successive layers of concrete on top of one other to build up vertical walls and domed roofs.

The key to the technology is a computer-guided nozzle that deposits a line of wet concrete, like toothpaste being squeezed onto a table. Two trowels attached to the nozzle then move to shape the deposit. The robot repeats its journey many times to raise the height and builds hollow walls before returning to fill them.

Engineer Behrokh Khoshnevis, at the University of Southern California, has been perfecting his "contour crafter" for more than a year. "The goal is to be able to completely construct a one-story, 2000-square foot home on site, in one day and without using human hands," he says.