As opposed to other roof structures, such as Mansard or Hipped roofs. If so, is it because there is a lesser distance between the internal heat source and the roof?
Hm. Tough one. Could be. I would think because there is less surface area.
For insulation, what is important is the material it is done and how it is positioned (different materials used on the same roof), and not it if flat or anything else.
No, it really does not matter what type of roof as long as the insulation is well done. But of course in a flat roof it is easier to reach all the points with ease whereas in sloping roof some areas may be inaccessible. But, with blow-in insulation that is not a big problem.
