Roof Drain Overflow Scupper

A primary drainage system is designed to remove water from the roof as quickly as possible.

Roof drain overflow scupper.

Scuppers shall not have an opening dimension of less than 4 inches. Cast options ranging from iron to stainless steel. In short a scupper is a detail that provides drainage to a roof system by allowing the water runoff from the roof to exit the roof through a metal edge parapet wall or through the deck into a downspout or leader not run through the interior of the building. Scupper drain 11 3 4 inches wide x 11 3 4 high x 8 long deep drain opening area with 4 in.

When scuppers are used for secondary emergency overflow roof drainage the quantity size location and inlet elevation of the scuppers shall be sized to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by section 1611 1. Where you must drain through the wall with a scupper the overflow must be three times the required size of the roof drain and have a minimum height of 4 and again be installed no more than 2 above the roof low point. While you must provide the overflow it can not be connected to a downspout. Scuppers will play one of two roles in a roof system.