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The Importance of Drainage for Your Commercial Flat Roof 

Drainage is an important part of any roof system. Your commercial flat roof is especially susceptible to the damages of improper draining. In this post, we will highlight the importance of drainage, especially on your commercial flat roof, by explaining the best options to ensure drainage as well as some of the dangers associated with poor drainage. 

The Dangers of Improper Drainage On Your Commercial Flat Roof 

Improper drainage on your commercial flat roof can spell disaster for not only the roof, but the entire building. Flat roofs tend to collect water much easier than slanted roofs which can lead to pooling, causing leaks, sinkage, and even collapse. That’s why it is so important to ensure your commercial flat roof has proper drainage.

While drainage is important to take water off of your roof, it is also important to transfer the water to a place where it won’t be problematic. The erosive properties of water are infamous and the improper diversion of water can lead to foundation damage which can end up costing significant amounts of money. 

Best Options for Drainage For Your Commercial Flat Roof 

You can make sure you get the proper drainage on your commercial roof through several strategies. 

Inner Drains 

Inner drains are placed inside the perimeter of the roof and are very effective at catching water where it would likely pool. Some roofs only require one while others can have as many as 10. The drains lead to pipes that feed away from the building, much like gutters. While this is one of the most effective ways to decrease water pooling, it can also be an extensive job installing them. 


If you have ever seen a ship, you will notice that there are small holes in the gunwales that allow water to escape. These are scuppers and work in the same way on commercial flat roofs. Instead, these are holes or drains at the bottom of the parapet that allow the water to escape to prevent pooling. These systems are relatively simple to install and can be quite effective. The only drawback is if there is significant pooling in only the center of the roof. At around $62 per scupper, it makes for a pretty affordable solution as well.


The tried and true method of water management is of course, gutters. Popular in both commercial and residential roofing, gutters have withstood the test of time as the system that most reliably transports water to safer locations. Gutters are the half cylindrical pipes on the edges of your roof that divert water away to areas where it is more safely deposited. Without them, the water would roll off the sides of your roof and could potentially damage your foundation. 

Ensure Proper Commercial Flat Roof Drainage with Supreme Roofing 

If you believe that your commercial flat roof is experiencing improper drainage, give the experts at Supreme Roofing a Call. Our professionals can inspect your roof, point out the problem areas, and offer a solution fast. Give us a call today or fill out our online form for all of your commercial roofing needs. 

Craig Rainey
Craig Rainey

Executive Vice President

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