Any chance this is possible? Do i have to turn it upside down due to the exterior columns only being attached at the top plate?
No need to reorient it, just make sure the thickness of the walls and columns is above the minimum values listed on the "Materials" page for the desired material. (The columns would count as "wires" in shapeways' terminology as they are relatively long and thin - best use the limits for "unsupported" wires as guideline if you can - although most if not all appear to be connected at both ends)
The model will be fragile though, since the basement seems to only be attached to the other floors through the stairs.
You need to mention the scale that you want to print in and the material as well. Then we can tell you if it will work or not. Or just give the general dimensions along with the wall thickness of the stairs and we can figure it out that way too.
Why print in one piece? I'd print it in parts and assemble it. Playing with LEGO as a kid should have taught you this skill well.