5 Common Causes of Commercial Roof Leaks

Why Is My Commercial Roof Leaking? 5 Common Causes of Commercial Roof Leaks

Rufus WestRoof Maintenance, Roofing Contractors

No one wants to see water leaking through their roof. Even with regular roof maintenance, harsh weather can roll through, and you can find a puddle on your floor.

Over the past 38 years, our team of roofing experts has seen this happen more than we can count. But if you are prepared and maintain the leak, you can prevent further damage to your facility and the property inside.

Signs of a Leaking Commercial Roof

  • Stained Ceiling/Walls – Whether you have ceiling tiles or other types of ceiling systems in your facility, extended exposure to water will create a discolored area of your ceiling.

Roof Leak in Office Building

Roof Leak in Office Building


  • Odor/ Mold – A foul smell in your facility could be a red flag for hidden mold. Mold grows in moist environments, so if water is continuously entering your building, there is a high chance that mold could grow and spread.

Read More: Mold Remediation in Commercial Buildings Guide from the EPA


  • Water Dripping/Puddles Inside – The most sure fire sign of a commercial roof leak is when you can visibly see water entering your building, whether it is a puddle on the floor or dripping above your head.

Read More: My Commercial Roof Is Leaking: What Can I Do?


Common Causes for Commercial Roof Leaks

Poor or No Drainage

When commercial roofs are installed, the contractor should take into account where the water will drain. There are multiple points of vulnerability when draining your commercial roof: drains, gutters, downspouts, and scuppers. These need to be regularly cleaned to ensure they are clear and moving water off of the roof.

When water is not draining from your roof properly, you can have standing, or ponding, water on your roof. In addition to sitting water risking a leak through the membrane, the water can add a lot of extra weight on your building structure.


Open Penetrations

Roof penetrations are found on many flat commercial roofs. Roof penetrations are HVAC units, vents, drains, pipes, gas lines and other systems that come through the roof membrane. While these are vulnerable areas for leaks, they can be properly sealed during a roof installation or spray coating.

Damaged Roof Flashings

A roof flashing is the pieces of metal that are installed around conjoining areas on the roof. Roof flashings are installed in areas such as chimneys, skylights, roof edges and interior walls. When a flashing is not installed correctly or, or when a metal flashing is aged, it can be damaged by wind or temperature changes, allowing water into the roof system.

Commercial Roof Repairs

Commercial Roof Repairs


Damaged Membrane

The membrane of a commercial roof is the waterproof layer. When there is damage to the membrane from the weather, foot traffic, mechanical damage or any other numerous situations, it can allow water to leak through the waterproof membrane and saturate the underlying insulation.

Sometimes there can be a quick patch to repair the area, other times you need to replace the insulation and large pieces of membrane.

Aged Roof

Most commercial roofing systems last between 15 and 20 years; this lifespan can vary depending on the type of roof you install on your facility. While enrolling into a roof maintenance plan can extend the lifespan of your roof, after a certain number of years, it’s time to replace your roof system.

Commercial facility building codes allow up to 2 roof systems to be installed on your building, after that, you will need to tear them off before installing another system.

What to Do When Your Commercial Roof Leaks

Whether you walk into a puddle in your facility or feel water dripping on your forehead, it’s always a stir of emotion when you are faced with a potentially costly roof project.

Don’t Panic!


That’s why we put together this action plan for when you find a leak in your commercial, industrial or manufacturing facility.


  1. Minimize Interior Damage – When you see water flowing into your building, clear the area of people, equipment, and supplies to reduce damage.


  1. Mark the Point of Entry – Make sure you mark where your leak is located. Marking the visible leaks is important for when you talk to your contractors and insurance agents.


  1. Look for More Problem Areas – Hopefully, your leak is only limited to one area, but chances are there are other leaks in your building. Look around your facility for more problem areas.


  1. Call a Commercial Roofing Contractor – After you maintain the situation…you have to get that leak fixed! Reach out to area contractors to have them assess your roof and provide a project quote.


Free Download: Roofing Contractor Quote Checklist

  1. Call Your Insurance Agent – If your facility has received internal or roof damage, make sure you let your insurance agent know.


Read More: Business Water Damage Insurance

  1. Review Your Warranty – Look back in your files to review your current roofing system’s warranty. Your roof may be under warranty from the contractor or manufacturer, and it may be covered depending on what the damage is from.

No matter how you treat a commercial roof leak, it’s important to remedy the problem before it grows. Even the smallest leak can cause serious problems if not treated. Water getting through your roofing system can cause considerable damage to your building from mold to structural damage.

If you are looking for maintenance, repair or replacement for your facilities roof, fill out our quote request form for your free no-obligation commercial roof quote from our team of experts.

My commercial roof is leaking eBook

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About the Author

Rufus West