In the house I'm building, I will be using a flat roof with a parapet around it. The total area will be around 120 sq meter and the roof will be a concrete slab (at least 8 cm).
What is the best way to drain it? People in Brazil don't like to use those kind of roofs so I can't get good info on the subject.
I will be waterproofing it using some type of asphaltic membrane rools that are covered in alumminum foils (for protection).
I'm on the starting phase of the construction, so I'm quite flexible with what I can do, but here we don't have fancy siphonic drains, mostly PVC pipes are used (100 and 150 mm).
BTW: If possible I don't want anything inside or below the concrete slab (I'm partial to scuppers).
EDIT: What about this idea: make the whole roof sloped (2% inclination) towards the back, and there use a single gutter with a tube down each end? Is that good design? I know that one end of the roof will be almost 30 cm higher than the other (the lenght is 13,5 meter), but since I'm at construction phase I can make the roof concrete slab sloped from the start.