Already some years ago (August 25th, 2014 to be exact), Andrey Rudenko finished printing his first 'house' to show the world it is possible to build a multiple story house with 3d printing technology. Rudenko created a concrete 3D printer for this task and showcased his vision by printing a beautiful (small) castle.
Read more about this project @ http://www.totalkustom.com/3d-castle-completed.html.