I'm 8 years late to the discussion, wondering how it turned out. All the links to pictures are long gone, so just have a limited imagination to work with. I say limited because we do things a bit differently here in the USA. Flat roofs (have a degree of
slope) drain to an outside part of the roof. thinkin.. the roof has a wall if you will, around a foot tall above the roof, the wall goes the perimeter of the roof, at the low part of the roof ya cut a hole in the foot tall wall to let the water drain out.
Those were used in Mexican type buildings. Modern days, we slope the roofs for multiple reasons.
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