Internal Roof Drainage

The drainage requirements for flat roofs on buildings present some special problems that we describe and illustrate here.

Internal roof drainage.

At page top and at left our photos show a low slope roof surrounded by a parapet. If water collects in one spot in the middle of your roof then installing an interior drain there to move the water is a good solution. Recess the drain below the roof surface. Properly slope the structural framing and deck minimum inch per foot.

Use an insulating fill or tapered insulation for slope. On large flat roofs mainly on commercial buildings or large residential complexes you ll likely find internal drainage systems. The most important factors in roof drain design are. Watch for clogs blockage at the roof drain or scupper.

Roofs of this design will have one or more roof drains or scuppers installed. Properly locate roof drains scuppers and gutters to remove water from the roof s surface. Internal roof drains these will drain to somewhere near the center of the roof and down through the building to underground storm mains or a detention pond. This form of roof drainage is preferred if a clean exterior appearance is desired.