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What is a Roof Scupper?

Most people are familiar with rain gutter systems. These are important additions to houses, allowing for rainwater to be safely directed away from the house foundation, preventing costly water damage to the home. But one thing these systems depend on is a sloping roof. Without a slope to the roof, the water has no way to be directed down into the gutter system. In these cases, the water surely must just pool up… or does it?

Many cities have large buildings with flat roofs. Many of them have decorative downspouts attached to them. So you might wonder—how is the water getting into the downspout? The answer to that question is: the roof scupper.

A roof scupper is, as you may have guessed, a drainage system for flat roofs. It enables water to move through a gutter system, and works in conjunction with downspouts. A scupper can be installed to carry water into a rain gutter, or directly into a downspout through a conductor head. As long as the roof scupper is clean and free of debris, snow, and ice, it should drain water nicely.  

Roof scuppers come in a few different types, and there are different shapes. Roof scuppers can be channel-type or through-wall type. Channel-type scuppers are either three-sided, or are simply a rectangular hole cut in the wall. These holes allow water to drain straight down the sides of your building, preventing water from pooling and leakage. Through-wall types are usually a steel box made of copper or galvanized steel. These form an integrated system that is flashed into the roof, and has a sealed faceplate on the exterior face of the wall.

A roof scupper should not be confused with a roof drain. Roof scuppers are part of the drainage system. They allow water to run off through a metal edge, parapet wall, or the flat roof into the downspout. This prevents water from puddling up on the roof and eventually making it way into the building’s interior. Roof drains, on the other hand, are assemblies where water runoff transfers through the roof drain and into piping. This piping then runs out to the building’s exterior. Roof drains can be installed in the middle of the roof. They’re connected to piping that will go through the building’s attic and out to the wall of the building’s exterior. A simple way to look at it is that roof scuppers drain water externally, through gutters and downspouts the outside of the building, whereas roof drains drain water internally, through pipes inside the building. It’s also important to note that the two are not mutually exclusive—it’s quite common to find a combination of both roof scuppers and roof drains on a single flat roof.

A roof scupper is not so expensive to buy. To install one, however, you’ll also need caulk to seal the joints, and you may also need to weld the scupper to the gutter downspouts. Scuppers include many different parts, and each state has different roofing codes to follow. Therefore, it’s best to have a roof scupper installed by a licensed roofing contractor. 

As mentioned above, water can puddle on a flat roof after a heavy rain. To make sure this doesn’t happen, it’s necessary to have a proper drainage system. A properly-installed roof scupper will allow for the water to be safely drained off the roof. If the drainage system backs up, however, you could end up with costly water damage. That’s why it’s important that the roof is checked regularly. Check tp make sure there are no clogs in the vent, along with no animal nests. Also check for corrosion. 

If you have a flat roof and you’re looking to install a new drainage system, scuppers can be very affordable. If the scuppers are the appropriate size, they shouldn’t get clogged with leaves or other debris (although it’s important to periodically check the scuppers to make sure they are problem-free). Also, because they drain the water outside the building, they drastically reduce the chances of leaky pipes causing water damage to the interior of the building. Make sure they’re properly connected to the downspout, however—otherwise, they could dump water near the building’s foundation, leading to costly water damage.