Andrey Rudenko is working on 3D printing (or possibly more accurately, "extruding") houses and large structures from concrete.
He's already built a mini backyard castle, and a prototype hotel suite. I'm not certain how the concrete is reinforced here.
https://s3-us-west-1.amazonaws.com/h...ete_castle.jpg
https://www.youtube.com/watch?v=2eNp6q35uRo
https://www.youtube.com/watch?v=zb3zuk1qNDk
More: Rudenko 3D Printer
