How to Select the Best Drainage System for Your Flat Roof

Flat roofs are popular in commercial construction and can be found on many homes and condos as well. Though there are numerous benefits to flat roofing, one of the main challenges is in settling on a proper drainage system. Many flat roofs have issues with water drainage, but with the right solution and proper maintenance you can avoid water pooling and leaks.

A. Clark Roofing & Siding LP., one of the most trusted Edmonton roofing companies providing residential and commercial flat roofing systems, is often approached by home and business owners who want to know more about drainage systems for flat roofing. The best drain for your building will depend on your building style and location, but we’ve put together a handy guide that can help you decide on the right system for your needs. There are three main types of drainage systems to help you with water flow on your building, including gutters, drains and scuppers.

1. Gutters

Just like most types of roofing systems, flat roofs can make use of gutters to drain away excess water. Open pipes running along the edges of the roof can stop water from pooling near foundations, doorways and windows.


  • Inexpensive: Gutters are the least expensive drainage solution.
  • Easy installation: Often the easiest to install, they are very effective at dealing with any amount of rain and snow.


  • More maintenance: In order to remain effective, gutters must be cleaned on a regular basis.
  • Winter freezing: When blocked with debris such as leaves and twigs, gutters can cause water to pool and ice dams to form in the winter.
  • Cleaning: The brackets and hardware can make them challenging to clean.

2. Drains

Flat roofs can also drain water via a system of drains located at certain points on the roof, generally towards the centre. These drains – which will often be covered by a strainer to keep out debris – connect to gutters and pipes inside of the roof.


  • All season drainage: As the pipes are protected inside of the building, they do not freeze during the winter and hardly ever need to be replaced.
  • Increase curb appeal: The drain can be placed strategically so it is out of the way or unseen, as no gutters or spouts are needed. Because the drain is hidden, a drainage system is also the most aesthetically pleasing solution.


  • Cost: Drains tend to be the most expensive system to install. Maintenance can also be more expensive for this system, as a professional is needed if a clog should happen.
  • Clogs: They can also become clogged if the proper strainers are not in place, meaning maintenance is required to ensure no debris is stuck in the drain.

3. Scuppers

If you’re really looking for value, then consider scuppers. Scuppers are essentially a series of outlets placed along the roof’s edge. Water drains through these outlets and into downspouts which direct it away from the building’s walls and foundation.


  • Ease of maintenance: Scuppers require almost no maintenance and rarely become clogged, provided the scupper is the right size for your building’s draining needs.
  • Value: Scuppers typically provide the best value for your drainage needs


  • Slope: For scuppers to work well, however, the roof does need to have a sloped structure which can direct water to the edges. They are not generally the best option for handling snowmelt, but they are highly effective for heavy rain

Have Some More Questions? Your Alberta Roofers Are Here to Help

The best flat roof drainage system for you will largely depend on your own unique needs and preferences. The Edmonton and Sherwood Park roofing contractors at A. Clark Roofing & Siding LP. will be more than happy to help you figure out what sort of drainage system is most suitable for your roof. We also offer flat roof installation, maintenance, and flat roof repair in Edmonton. For more information on flat roof drainage, just contact A. Clark Roofing & Siding LP. today.

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