Scuppers – A Flat Roof Drain System for Commercial Roofs – Watch video

What is a “Scupper”?

Scuppers are drain openings, placed through walls, that drain heavy water and debris away from commercial flat roofs.

Installing a scupper that leads out into a drain

Installing a Scupper on an EPDM Flat Roof

Watch the video below.  We are cutting away the edge of an EPDM rubber roof to lower it to install a scupper that will drain into a gutter. It is important to make the scupper wide enough to handle the amount of water drainage typical for each climate. A scupper that is too narrow will become easily clogged with leaf debris, causing the pooling of water.

Another video showing the installation of a scupper

Proper Placement and Size of a Scupper is Important

Proper positioning and size of a scupper is essential for water and debris drainage. The video below shows how we lowered and increased the size of an existing scupper, in a parapet wall. It was positioned too high, and it was too narrow which made it difficult to clean. We found that trapped tennis balls were restricting proper drainage.
Fixing a leaky scupper. This was a messy job

Scupper Placement on Commercial Flat Roofs 

It is very important to install scuppers in the proper places on commercial flat roofs. There are several factors to consider:

  • Find points on a roof where water will drain naturally
  • Make sure that runoff from the scupper does not accumulate around a foundation or wall
  • Make scuppers wide enough to handle large amounts of water and debris
  • The scupper must be accessible for debris removal and maintenance

An Incorrectly Installed Scupper

The image below shows an example of a scupper that was incorrectly installed on a flat roof. Water could not flow naturally from that position on the roof, which created ponded water that will eventually cause the rubber membrane to fail prematurely. If scuppers are the only way to drain water from a roof, they should always be positioned lower than the roof surface itself.

A Scupper Can Prevent Pooling Water

A scupper can be installed on almost any edge of a flat roof when there is an issue of pooling water. Watch the video below.

Scuppers Flat Roof Draining - An incorrectly installed scupper causes pooling water.
This scupper is place slight higher than the roof surface causing water to pool


Scuppers are types of drains for both commercial and residential flat roofs. They must be properly installed to accommodate the volume of water and debris that needs to flow off of a roof and away from its foundation.

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