I wouldn't call that a true Mansard roof, and the style isn't something of a time period or anything that would be defined (i.e. Bungalow, Prairie, Ranch, Craftsman, etc). The roof looks like a parapet, which is done typically to hide mechanical equipment, or maybe they had intended for it to be a roof deck. The style of that in particular looks like what a lot of commercial building do to blend into a residential neighborhood. I agree with Karen, it could be modernized. It looks like from the photo it already has stucco. I would clean that up and give it some contrast with a fresh paint color. And the roof, I wouldn't stucco it because parapets are still designed with runoff in mind, it could leak and run down the inside of the walls if you made it stucco (but you would have to have a professional look at it closely, I can't tell from the picture). I would consider a clean fresh asphalt shingle if your goal is to modernize it's appearance.
