Why Commercial Roofs Leak. These are the Most Common Causes

There are two commercial roofing “facts of life” that are inevitable. The first fact: you will always need a reliable, high-quality commercial roofing system on your building. The second fact: that commercial roofing system will, at some point in its lifespan, have a leak that will need to be resolved.

As commercial roofing systems age, roofing leaks become a common issue that must be confronted before they can cause any damage to the building below. The best way to deal with commercial roofing leaks, and even prevent them, is to understand the root causes of the leaks. Once you know what causes them, you can work on preventative measures.

These are the most common causes of commercial roofing leaks.

Poor/Improper Drainage

The most important way to prevent leaks on a commercial roof is to ensure that it can adequately drain water after heavy rain or snowfall. Poor and improper drainage causes standing (or ponding) water, which can erode even new roofing systems. The most important thing a roofing contractor can do when installing a commercial roof is ensure that there is a proper drainage system to accompany it.

If you are noticing leaks in your commercial; roofing systems (stains on the ceiling, etc.), the most likely culprit is your roof’s drainage system. A quick trip up to the roof will likely reveal standing water.

Unlevel Roofing

Standing water can also be caused by a commercial roofing system that is not properly leveled. While the drainage system will take the water off the roof, the water still needs a means of getting there, which requires a slight pitch that will allow water to make its way to the edge of the roof. If there are significant peaks and valleys in your roof, water can easily pool in some of the sunken valleys. Even the slightest variation in pitch can cause water to pool, ultimately leading to leaks.

Damage to Seals or Flashing

Sealants and flashing are used to prevent water from entering your building through the gaps around your HVAC systems, vents, gas lines and other opening in your commercial roof. If these areas are not properly sealed, or if the flashing is damaged or missing, water will inevitably leak through into the space below. This is why frequent commercial roofing inspection and maintenance are important. Getting up on your roof to look for damaged and/or missing flashing will stop leaks before they can seep through any openings.

Aged Membranes and Roofing Components

Ultimately, the age of your commercial roofing system will cause materials (like roofing membranes) to become worn and damaged. Prolonged exposure to sunlight, harsh weather and other natural elements will cause wear and tear on all roofing materials, which is why it’s important to invest in commercial roofing repair and replacement throughout the years. These types of repairs (and even outright replacement of commercial roofing systems) are necessary investments that will prevent costly damages from occurring over the years.


Need a quote on your commercial roofing repair or replacement? Contact Schmidt Roofing today.


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