What Are Roof Scuppers And How Are They Used?

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What to know about roof scuppers

One important component of any roof is the drainage system. You need to be sure that rain and other water can drain from your roof, so that it doesn’t pool and create any damage. There are a couple of options to channel water, with cuppers and traditional roof drains being the two that are typically utilized individually, or together.

What is a roof scupper?

A roof scupper is a drainage system that is an outlet in the wall, normally covered in sheet metal, that allows water to drain through an opening in the roof edge.

Roof drains and roof scupper drains, and while often thought of as similar in that they both prevent standing water, they are not actually the same. A scupper and a roof drain differ because a roof drain uses an actual piping system, whereas a scupper generally allows water to flow out from the end of its spout down the side of the building. A scupper is usually placed in the parapet wall.

Roof scuppers are used in a lot of different types of construction, but you’ll usually find them in apartments and commercial buildings. Homes with flat roofs also sometimes may have them.

There are multiple benefits to using a scupper over a roof drain, and there are also benefits to using a roof drain over a scupper. Both can be used as a kind of drainage system, but what determines which one will be used in the construction of a building depends on things like the kind of roof you have and the building codes that you need your roofing drain system to meet.

Roof Scupper FAQS

What are some of the main benefits of roof scuppers?

Roof scuppers tend to be cheap and on the easier side to install. While they sometimes clog (more on that below), if they’re properly sized this shouldn’t happen often, making regular maintenance rare and usually unnecessary. They also don’t interfere with the interior systems of the building, meaning if you’re doing any kind of renovating, you don’t need to get involved with interior piping, which makes the whole job much easier and cheaper.

Scuppers are utilized as either the main drainage system for the roof or as a tool that prevents water from pooling on the roof area.

What are some of the main downsides of scuppers?

There are several. The biggest and most consistent thing that can happen is clogging if your scupper isn’t the proper size for the level of flow it’s going to receive from your roof. You need to have enough space inside the scupper so that it doesn’t get clogged by things like mud, sticks, and leaves.

Freezing is also a possibility if you’re in a region where it regularly gets cold. The clogging can become a larger problem and lead to other issues on a flat roof due to water pooling on the top.

In what situations should a roof drain be used over a scupper?

The two are actually most commonly utilized together on a roof, but to prevent both clogging and to have a clean, smooth drain, the two systems should both be positioned where they fit best. Roof drains, for example, typically start with a grate on the roof, which can be very helpful if you’re dealing with a lot of clogs in scuppers you may already have.

There may sometimes be debris on your roof, but depending on the type of building, that may be easier to clean than, say, clearing a clog on the inside of your scupper on a regular basis. Most buildings will have both scuppers and roof drains. The trick lies in knowing where and when to place which, and for what reason.

The logic is simple: generally, roof drains to take care of ponding water and excess overflow, while a scupper can deal with water that the roof drains don’t cover. They also don’t need maintenance or cleaning nearly as much.

How do you know what size scupper to get?

To begin with, many different building codes in different cities have the following as a rule: a scupper shall not be less than four inches when it comes to the width of its opening. This tells us something: smaller scuppers tend to be bad, especially when we’re talking about larger amounts of water flowing through.

It’s good to have larger, wider scuppers. This is because things like leaves and sticks won’t get stuck, and they’ll wash through the scupper and go onto the ground with the water.

How do you install a roof scupper on a flat roof?

The easiest way to do this is to cut a wide chunk through the roof and clean it out. The scupper needs to be wide enough so debris doesn’t get caught in it, but it also needs to be placed in the right spot on the roof surface. A scupper won’t do much good if it’s not where the water is sitting on a roof.

It also helps if there’s a slight incline added to the flat roof so the water naturally flows in the direction it’s supposed to. Once you’ve got a clean hole through the side of the roof, you can add in the sheet metal and nail it down. A properly made scupper, wide enough to handle debris, can deal with the drainage of a massive downpour of rain and leave you with no pooling at all on your flat roof.

It’s a fairly easy renovation that can be an excellent combatant to water damage or other water-related roof issues, and if you have drainage systems that aren’t doing the job currently, a roof scupper is a good option to consider.


Roof scuppers have an important place in construction and as a water drainage system, whether they’re used as the primary drainage system or as a secondary/backup option.

They’re useful and cheap to install, and it can benefit your building to have them placed in the right spot. However, they have their own downsides and the best roof protection from water generally involves both roof drains and roof scuppers.

Depending on the building, you might be able to manage water from the roof with just one or the other.

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