Learn About Flat Roof Drainage Solutions

Flat Roof Drainage
Learn About Flat Roof Drainage Solutions

Flat roofs are not places where water automatically sloughs off just from the force of gravity and the architecture of the structure in question. So, this is in stark contrast to pitched roofs, dormer roofs, gabled, roofs, hip roofs, and gambrial roofs, which are all common and where gravity and design takes care of things.

A flat roof without an appropriate answer or system for draining is going to collect water when it gets wet. That means that if you do not deal with optimizing water flow, and possibly snow melt depending on where you live, then you are going to have problems down the road. Poor drainage is an issue for any roof, but it’s especially bad for flat roofs.

Debris Removal

The first possible problem is the collection of debris and leaves, all of which can retain water. Water might ‘pond’ together, which creates spots for plants to grow or even cause buckling. Tar and caulking can see deterioration, ruining the seals the structure counts on to prevent leaks in chimneys, vent pips, and skylights. Winter ice can increase the very load the roof has to handle, stressing the roof and the entire building or home.

Fortunately, there are flat roof drainage solutions. Actually, many varying options exist, but there are three common ones in particular covered here that your contractor or structural engineer might discuss with you.

Flat Roof Option 1: Interior Drains

The first one is a system of drains, which also might be referred to as interior drains. This is not unlike a simple drainage system you know from bathroom showers. Professionals strategically place them in particular spots so that when water starts gathering about, it gets funneled down through pipes and out of the building. The collection points are usually in the center of the roof. Not only does this system drain the roof, it also usually prevents the need for downspouts and gutters. On the other hand, interior drains do need regular cleaning.

If debris or leaves block things, then water ponding can happen. Your rooftop solutions professional might be able to customize a drain though.

Option 2: Traditional Gutters

Gutters are a second possibility, since the lack of them or something else means that water either stays up there or just runs off any side or edge it can. That not only means waterfalls over entries and windows, it actually wears down walls over time.

Like drains, they have to be kept clean with routine maintenance.

Option 3:  Scuppers

Scupper Drain
Scupper Drain

Scuppers are the third common option among flat roof drainage solutions. They’re sort of like gutters in how they gather water and funnel it from a structure, in that they create openings in a roof’s parapet walls, where water pours through downspouts and then guided away from the foundation of the structure. Clever designs use these to water flowerbeds directly. Unfortunately, as creative and even pretty as these can look, scuppers work better on pitched roofs then flat ones. Snowmelt is also not handled well by this system, although heavy rain is. Debris and leaves still need cleaned out.


If your home or business needs flat roof drainage solutions, the answers are certainly out there. Work your roofing contractor to consider these three options as well as any other possibilities he or she might recommend for your structure.

While each possibility has its own benefits and drawbacks, customization and good design can create a drainage answer that keeps your flat roof from buckling under the weight of ponding, while providing outflow that does not threaten your foundation, disrupt entry points, or flood parking spaces. Just remember that each one needs to be kept clean.

Looking for Flat Roofing Solutions?

Are you in the market for a new flat roof on an existing business? Looking for a trusted contractor for new commercial construction?   TRI Roofing is a fully insured and licensed commercial roofer and home improvement contractor and are dedicated to serving the Triangle’s roofing needs by providing excellent service, and the absolute best workmanship and products.

We strive to be the best at everything we do: that means the best price, the best service, and the best quality to meet your individual requirements.  Give us a call today at (919) 296-0017.

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