-Use pillars on the first floor to create the shape of the house. Fill in every space inside the shape, except a spot for a staircase. On the second floor, build the house. After that, enable the move_objects on code, go to the first floor, and delete the pillars. You should now have a staircase going up to a house that is floating.
-Build a house with two floors. Build nothing on the first floor and everything on the second floor. Enable the move_objects on code and remove the lower level floor. You don't need to put any pillars.