This is a building I designed for a small shop+office building for my train layout.
The building and windows should print fine in the orientation shown. You might need supports for the building window openings, depending on your printer.
I have found I get best results on this style of roof by printing it vertically with a 15mm brim for stability. This eliminates the amount of supports needed if you were to print it flat, meaning you'll have a smoother texture on the underside from no support clean up.
You can cut your own flat roofs for the brick office portion and indoor office part, out of sheet styrene or thin craft foam.