Flat roofs: build-up, drainage and main advantages
On a section drawing of a flat roof, trace the path a raindrop would take from the high point to an outlet or the roof edge. This shows where the roof needs a fall and where a junction must maintain the continuity of the waterproofing. The insulation limits heat loss, while the supporting deck carries the loads. The order of the layers depends in part on whether the design uses a conventional or an inverted roof. This guide explains how to read both arrangements, which details to look for at parapets and service penetrations, and what determines whether water drains away.









