3D printer could build a house in 20 hours

An engineering professor, Behrokh Khoshnevis, at the University of Southern California, is really thinking big: He has figured out a way to build housing with a giant 3D printer.

Here's how it would work, according to the blog Pop Sci. The apparatus, instead of being the size of your typical laser printer, would actually be somewhat bigger than the house it would build through a concrete layering system called Contour Crafting.

The professor explained the process in a speech at the TEDx conference, which you can watch. (Start at 4:30 to see the animation demo.) In the video, the professor demonstrates how the machine lays down a concrete foundation, puts up walls, even inserts wiring and plumbing, and eventually constructs an entire building, which Professor Khoshnevis says can be completed in less than a day. (All that's left to add are doors and windows. ) Robotics could even be used to add details like tiles, says the professor.

Khoshnevis doesn't have just efficiency in mind—he wants to end the scourge of slums in the developing world. The system would be right for emergency, low-income, and commercial housing, notes the Contour Crafting website, such as in areas devastated by a natural disaster. Mechanizing home building would be cheaper and more efficient, Khoshnevis argues.

This kind of technology could also be helpful when humans aren't around, say on Mars or the moon, to set up housing before humans arrive.

As stated on the Contour Crafting website, "Contour Crafting technology has the potential to build safe, reliable, and affordable lunar and Martian structures, habitats, laboratories, and other facilities before the arrival of human beings."