We love flat roofs at Transcona Roofing! But flat roofs rely greatly on proper drainage of rain and snow melt to preserve their integrity. Without proper drainage, water can pool that may cause leaks, leading to ice formation in the winter, and deteriorating the roof membrane over time. The following 3 methods are the most common types of drainage that work best for flat roofs.

Interior Drains

This method of drainage is the most common, with drains typically placed at intervals at low points of the roof so that water can effectively travel off of the roof. The drains are often topped by a strainer that prevents leaves and debris from getting into the pipes. They are aesthetically pleasing because all of the components are located inside the roof and invisible to someone looking at it from the outside. Due to the nature of their internal piping systems, these tend to be more costly to install as compared to exterior systems that we will look at next.


Scuppers are outlets placed on edges of roofs that allow for external drainage of water away from buildings. Coupled with downpipes or rain water leaders (RWL’s), they keep the walls of buildings dry and prevent too much exposure to water. Scuppers are more cost effective than internal drains, but they work best when all of the water is directed to them using a tapered insulation system or a sloped structure. They are a good solution for areas that frequently get heavy rains, but are not ideal for dealing with snow melt.


Gutters are open pipes that are attached to the edges of the roof. Similar to the gutters many homeowners have at the eaves of their shingles, they collect water as it drains off the roof and carry it away from the building. They are generally the most cost effective drainage solution since they can be attached to a finished roof without any modification to the roof itself. They are also good at dealing with variable levels of rain and snow. As with drains and scuppers, gutters do regularly need to be cleared of debris and cleaned in order to continue functioning properly.

Deciding what type of drainage is best for your facility should be determined by your building consultant or building design team. In addition, you should always make sure that the roofing contractor you hire is experienced in installing all three of these drainage systems. While a proper drainage system design is essential for the overall reliability of the roof, a quality installation ensuring the design is implemented properly is key.

Transcona Roofing has a long history of experience with flat roofs and drainage systems on flat roofs. If you have a flat roof and you are ready to maintain or install your flat roof and drainage system, please call Transcona Roofing today to schedule an appointment or consultation.

Rest easy knowing that Transcona Roofing has you covered. It's about Installing Confidence!

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