Roof Scuppers And Their Usage – Do You Need One?

Beyond gutters – Discover the unexpected advantages of roof scuppers and upgrade your drainage game

Roaming through city streets, you might have noticed unique fixtures on towering buildings with flat roofs. These adornments seamlessly blend with the architectural style, often resembling decorative downspouts or side spouts. Yet, have you ever pondered their purpose? Well, guess what? You’ve passed by countless times, never knowing these fixtures are roof scuppers, which are an integral part of the building’s drainage system.

Perhaps no one ever mentioned it, leaving you curious about what a roof scupper does. Simply put, it’s a vital component in the drainage setup for flat roofs, guiding water through the gutter system. Intrigued to delve deeper into understanding what a roof scupper actually is and why it matters? Give this blog a read to ensure you make the best decision for your new roof installation!

What are Roof Scuppers?

  • The International Building Code describes a roof scupper as an opening in a wall or parapet that helps water move off a roof. Sometimes, people call them “roof scupper drains” or just “scupper drains,” which makes sense because they help drain the roof. However, it’s important to note that “roof drain” means something different.

In some places like the American Southwest, roof scuppers with spouts that stick out beyond the wall are called “roof canales.” They’re commonly used to collect rainwater. Scuppers act like pathways for water to flow through walls or raised edges around a roof, like gravel stop edge metal.

  • The main roof scuppers usually direct water off a low-sloped or “flat” roof into a box that connects to a downspout or gutter. If there’s too much water, overflow roof scuppers let it run down the building’s side.

Typically, a roof scupper is part of a peripheral roof drainage system. This type of system lets water drain off the sides of the roof rather than through the roof itself using internal drains.

  • When walls separate different sections of a building’s flat roof, there are often scuppers in the walls. These scuppers help water drain from one flat roof section to another. Interesting, right? Now, let’s explore the types of roof scuppers!

Types of Roof Scuppers

Roof scuppers typically appear in two main styles: the open scupper, which resembles a three-sided channel open at the top, and the through-wall scupper, essentially a rectangular hole in the wall.

Thru-Wall Roof Scuppers

  • Thru-wall or through-wall scuppers often feature a lining made of sheet metal like galvanized steel or copper. Aluminum isn’t commonly used due to its challenging formability and on-site soldering requirements, unlike other metals commonly used in roof construction.

This metal element is referred to as a “scupper box.” It’s incorporated into the roof system, secured or integrated within the interior side of the wall. Normally, it extends outside the wall and finishes with a faceplate sealed with caulking or sealant around it.

Channel-Type Roof Scuppers

  • The channel-type roof scuppers usually have metal linings, which are connected with the coping or other edge metal. These linings are also flashed into the roof membrane for added durability and protection.

Sometimes, alternative materials like liquid-applied waterproofing resin might be used to line the roof scupper hole, although this is less common.

  • In instances of single-ply roof membranes like TPO roofing or EPDM, the roofing material often extends inside the scupper. It lines the entire visible surface of the scupper box, forming a bond with the metal for added strength and resilience.

How Does a Roof Scupper Differ From a Roof Drain?

The difference between a roof scupper and a roof drain might surprise you, as they seem quite similar in a roof’s drainage system.

  • A roof scupper is a crucial part of the drainage system that enables water to flow off the roof. It does this through a metal edge, parapet wall, or directly from a flat roof into a downspout. Its purpose is to prevent water from pooling on the roof and entering the building’s interior.

On the other hand, roof drains are assemblies designed to channel water runoff through piping that extends to the building’s exterior. These drains are often situated in the middle of the roof and connected to piping that runs through the attic, directing water out to the sidewall of the building exterior.

Advantages of Roof Scuppers

  • Roof scuppers offer several advantages in a building’s drainage system:

Efficient Water Removal

  • Scuppers efficiently drain water from the roof, preventing ponding and potential water damage. They facilitate swift water runoff, reducing the risk of leaks and structural issues caused by standing water.

Prevents Interior Damage

  • By directing water away from the building’s interior, scuppers help prevent water intrusion, mold growth, and damage to ceilings, walls, and valuable assets inside the structure.

Reduced Maintenance

Properly installed scuppers can decrease the need for frequent roof maintenance by effectively channeling water away from the roof’s surface and preventing debris buildup in gutters or drains.

Structural Integrity

  • They contribute to maintaining the structural integrity of the building by minimizing the accumulation of excess weight due to standing water, which can compromise the roof’s stability over time.

Design Flexibility

Roof scuppers can be integrated into various architectural designs and styles, offering flexibility in aesthetics while serving their functional purpose.

Compliance with Building Codes

  • In many areas, including roof scuppers as part of the drainage system helps comply with building codes and regulations related to proper water drainage from roofs. Hence, you should always work with a roofing contractor that understands these codes and requirements.

Disadvantages of Roof Scuppers

roof scuppersWide scuppers typically experience minimal clogging, offering reliable drainage compared to smaller scuppers and downspouts, which are more prone to blockages.

  • Although buildup in a downspout may not immediately cause interior water intrusion, it can result in water pooling on a flat roof. Over time, this accumulation could potentially lead to issues such as mold, mildew, and leaks.

In certain scenarios, scuppers without a downspout or lacking proper sealing to the top of the downspout can direct water down the building’s side. While this configuration may not be ideal, it can aid in exterior water drainage.

  • However, it’s essential to note that this kind of drainage might potentially cause foundation issues or basement flooding in a commercial building.

But if you look at the bigger picture, roof scuppers play a crucial role in efficiently managing water runoff, protecting the building structure, and reducing the potential for damage caused by water infiltration.

If you need an effective drainage solution for your commercial roof, roof scuppers stand out as an excellent choice for reliable results. It’s crucial, however, to entrust this task to licensed and experienced professionals.

If you are in search of a dependable roofing contractor, consider reaching out to Dupont Roofing. Our team comprises highly skilled experts capable of handling roofing projects of any complexity with exceptional results. Contact us today at (202) 840-8698 or complete our website form to schedule a free consultation and discover how we can assist you!

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