I have a patio with a 13ft(4m) by 26ft (8m) Roof, the slope runs vertically down the short (13ft) side.. and the height difference from the high point to the low point is only about 10in (25cm). ...
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 ...