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All About Roof Slopes on “Flat” Commercial Roofs

Posted by Art Valentz on October 19, 2022

Commercial roofs often look flat, but no commercial roof - or any roof, for that matter - is completely flat. Even on a roof that looks completely flat, there is a subtle slope (also called a pitch) that is important for the functionality and performance of that commercial roof.

A proper slope on your commercial roof can prevent a variety of problems from occurring, so if your commercial roof was built by a well-trained and experienced contractor, you can expect that your commercial roof has a slight slope to it, no matter how flat it appears to be. The more you know about your "flat" roof, the easier it will be to maintain it and extend its service life.

Why Slope Is Important

Slope serves a variety of functions on a flat roof. Even a subtle pitch that is too slight to detect can help your flat roof maintain its functionality. Here's why:

Prevent Ponding

Water will automatically pool at the lowest point on the roof - a problem that's commonly called "ponding." Ponding can cause the roof membrane to deteriorate, may lead to a collection of algae or mold on the roof, and ultimately, can cause the roof to degrade with time. If you're ever on your flat roof and notice a collection of water on the roof's surface, this is a sign that your flat roof isn't properly pitched and may require repair. 

Allow Water to Drain 

Flat commercial roofs should slope toward a drain or a gutter that allows all water to run off the roof and into the ground around the building. This slope prevents the ponding problem. It's important to keep gutters and drains properly cleaned to prevent water from collecting around these important systems. 

Maintain Your Roofing Material

Because your flat roof is slightly sloped, your roofing material should remain (overall) dry and free of mold. This makes it easier to maintain your roofing material, thus leading to fewer repairs over time. This also makes cleaning your commercial roof a little easier, as removing mold and algae can be time consuming. 

Allow Your Roof to Shed Debris

The slight pitch on your flat roof will also allow your roof to shed some debris, like leaves, twigs and even garbage. This debris will be carried away on the running water flowing down to the drain. However, flat roofs are not especially good at shedding debris, even when properly sloped. It's important to inspect your flat roof on a regular basis and remove debris multiple times throughout the year. 

Benefit of a Nearly Flat Roof

Commercial buildings are constructed with flat roofing material for a variety of reasons. Some of the reasons that commercial buildings come with flat roofs include:

Equipment Storage

Flat roofs are a place where equipment (such as plumbing, HVAC equipment, ducts and more) are often stored. Depending on how large your flat roof is, you may or may not have much room for equipment storage. 

PHP rooftop support systems improve rooftop storage space by raising items off the roof and allowing for easy access under that equipment. At PHP, we sell everything from pipe supports to duct supports and equipment supports to keep all your rooftop equipment safely off the ground. 

Easy Roof Access

Walking on a flat roof is much easier than walking on a sloped roof, which makes it easier for your maintenance crew - and any roofing contractor crew - to access your roof for repairs and maintenance. Flat roofs also provide the ideal surface for roof walkway systems for even easier access.

Less Roof to Maintain

Sloped roofs automatically require more material, because the surface area of the roof is much larger. This means that sloped roofs can be more expensive to build and may incur higher maintenance costs than a standard roof. 

Energy Efficiency

Steeply sloped roofs have high points and low points. The highest point of your steeply sloped roof is where warm air will congregate. This sloped configuration can make heating and cooling challenging throughout the year. Meanwhile, low-pitch roofs have no place to shelter hot, stagnate air - which makes these roofs more energy efficient. 

How to Maintain Your Flat Roof

Flat roofs have many advantages, but they definitely need regular inspections in order to maintain their functionality and structural integrity. Pooling of water and debris can lead to problems like deterioration of your roofing materials, so it's important to catch these problems in their early stages.

It's also important to ensure that you're using proper equipment supports for your low-slope roof. Equipment supports keep your roofing equipment off the surface of the roof, which protects your roofing membrane. For more information about roof slope and how equipment supports can protect your flat roof from damage, contact PHP Systems/Design. We'll provide pricing and a quote for the equipment you need.

Topics: Roofing Management

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