What Are Roof Scuppers?

If you’re responsible for a commercial building, you’ve probably come across the term “scuppers” when discussing drainage or water management. But what exactly are they—and why should you care? At Weather Shield Roofing Systems, we’ve been helping businesses manage water and prevent roof damage for over 40 years, and we know that poor drainage is one of the biggest threats to your roof’s lifespan and performance. 

Whether you’re facing standing water on a flat roof, mysterious leaks, or just want to better understand how your drainage system works, scuppers are a crucial piece of the puzzle. Let’s break it all down in simple, clear language. 

What is a Roof Scupper? 

A roof scupper is a drainage opening in the parapet wall or edge of a flat or low-sloped commercial roof that allows water to flow off the roof and away from the building. It’s essentially a hole in the side of your building—intentionally placed and often outfitted with downspouts or conductor heads to direct rainwater safely away. 

Unlike internal roof drains, which funnel water down through the building’s plumbing system, scuppers let water exit horizontally through the sides of the roof structure. 

Why Do Commercial Roofs Use Scuppers? 

Flat and low-slope commercial roofs don’t have the benefit of gravity to shed water quickly. That’s why good drainage design is critical. Roof scuppers offer a straightforward way to reduce ponding water, which can lead to: 

• Membrane damage 

• Accelerated roof deterioration 

• Increased weight load on the roof deck 

• Costly roof leaks 

Scuppers are often combined with internal drains and gutters to create a complete drainage system. For many commercial buildings, they serve as the primary or secondary drainage solution—especially during heavy rain or snowmelt. 

How Are Scuppers Different from Gutters and Drains? 

You might wonder, “Don’t gutters and internal drains do the same job?” 

Here’s a quick comparison to clarify: 

Each method has strengths, but scuppers are especially useful for handling heavy rain events and serving as emergency overflow in case other systems get clogged. 

What Types of Scuppers Are There? 

Scuppers come in different designs based on the building’s needs: 

• Through-wall scuppers: Pass directly through the parapet wall and often connect to a downspout. 

• Spout scuppers: Extend beyond the wall like a spout to allow water to fall freely away from the building. 

• Box scuppers: Larger, rectangular scuppers with conductor heads to collect and redirect larger volumes of water. 

The type of scupper you need depends on your roof layout, rainfall patterns, and local building codes. A commercial roofing contractor can assess your system and recommend the best fit. 

How Do Scuppers Help Prevent Roof Leaks? 

Scuppers reduce the risk of roof leaks by: 

• Eliminating ponding water, which breaks down roofing materials over time 

• Preventing ice damming during freeze-thaw cycles 

• Allowing overflow drainage, which is essential during downpours 

Think of them as a release valve. When your primary drainage system gets overwhelmed or clogged, scuppers step in to protect your building and investment. 

Do Scuppers Need Maintenance? 

Absolutely. Just like any part of your roofing system, scuppers need regular inspection and maintenance to stay effective. 

Here’s what we recommend as part of your ongoing roof maintenance plan: 

• Remove leaves, debris, and bird nests 

• Check for rust or corrosion on metal components 

• Make sure water flows freely through connected downspouts 

• Inspect for cracks or sealant failures around the scupper opening 

We include scupper inspections in our Max Life™ Roof Care program to ensure you’re catching potential problems early and extending your roof’s lifespan. 

Can Clogged Scuppers Cause Roof Damage? 

Yes—clogged scuppers are a serious issue. 

When scuppers are blocked, water can back up onto the roof, causing: 

• Roof membrane deterioration 

• Leaks into the building interior 

• Structural damage over time 

In winter, trapped water can freeze and expand, making the problem even worse. It’s a silent threat that’s easy to overlook—until it causes thousands of dollars in damage. 

That’s why proactive roof inspections and routine cleanings are essential, especially before and after seasonal changes. 

Should I Upgrade or Install Scuppers on My Commercial Building? 

If you’re dealing with any of the following issues, it might be time to look into scuppers or improve your existing setup: 

• Standing water or ponding 

• Frequent roof leaks 

• Overflowing gutters during heavy rain 

• Inadequate internal drainage 

We’ve worked with many building owners who didn’t realize their drainage problems were rooted in poor scupper design—or the complete absence of scuppers. 

A proper evaluation by a commercial roofing expert can determine if your roof would benefit from additional scuppers or an updated drainage plan. 

How Much Does It Cost to Repair or Install Scuppers? 

The cost depends on several factors: 

• Type and size of the scupper 

• Location and accessibility 

• Need for custom fabrication 

• Whether downspouts or drainage boxes are included 

Simple repairs might cost a few hundred dollars, while full installation on a large commercial roof could range from $1,000 to $5,000 or more. The good news? Investing in quality drainage now saves thousands in emergency roof repair costs down the line. 

How Can Weather Shield Help? 

At Weather Shield Roofing Systems, we believe in educating and empowering building owners to make smart decisions. If you’re not sure whether your scuppers are working properly—or if you even have them—our team can help you evaluate your current drainage system, identify risks, and recommend cost-effective solutions. 

Whether it’s installing new scuppers, repairing existing ones, or keeping them clean as part of our Max Life™ Roof Care program, we’re here to help you protect your roof investment for the long haul. 

Need a hand with your drainage or roof inspection? 

Contact us here and speak with a commercial roofing expert today. 

Ben Cornell

Account Executive

Ben Cornell is a lifelong West Michigan resident who began his career in commercial roofing in 2006—originally just looking for a summer job to help pay for college. What started as temporary work quickly turned into a lasting career as he steadily advanced through roles in estimating, project management, service leadership, and sales. Today, he serves as an Account Executive at Weather Shield Roofing Systems, where he continues to thrive in a company that has supported his professional growth every step of the way. Ben’s long-standing commitment to the commercial roofing industry is fueled by his passion for helping clients and the strong team culture at Weather Shield.