The concrete texture looks a bit bad in my opinion and the interior could use some more detail. It's to empy now.
Also maybe you should add some dirt at the base of the building, seeing as the grass is up to the building it the base of the building would get dirty.
And whats up with the roofshape? Should i be able to look at the top of the roof?
Jack
http://www.coloredfloorplans.com