What are the common causes of commercial roof leaks

Knowledge is power, and knowing what can cause a commercial roof leak will arm you with the tools and awareness of what to look for, and ultimately could save you from further damage and from losing thousands of dollars.


Before diving into the causes of commercial leaks, it is important to know the signs of a leak. This will allow you to identify a problem before it becomes uncontrollable. The signs include:


  • Stained ceiling or walls
  • Visible damage to roof or flashings
  • Odor and mold
  • Water dripping or puddles inside your building
  • Higher energy bills


For a deeper look into these signs, visit our previous blog : How to spot a leak in your commercial roof.


Now, what are the common causes of commercial roof leaks?


Penetrations, Punctures and Other Damages to the Roof Membrane


Some penetrations are unavoidable; vents, HVAC units, drainage and pipes. While these penetrations are necessary, they unfortunately can create a void in your roofs overall coverage. This is why it is important for these areas to be watched carefully during installation to ensure zero voids or cold welds.


A commercial roof's membrane is often breached due to heavy foot traffic, heavy equipment, and debris. Make sure the surface of your roof is being maintained and you are quickly repairing when ever you notice rips and tears.


An Aging Roof


A commercial roof generally has a lifespan of 20 years, even with upkeep and maintenance. If your roof has passed it's 15 year mark, it is advised to begin keeping a closer eye on it.


Keep in mind that while a commercial roof is expected to last 20 years, constant exposure to heat and sunlight, or heavy storms and snow, can prematurely age your roof.


Drainage System Issues


A roof should have gutters and internal drainage pipes to keep water from ponding at the top, but if any of these systems are failing or not working properly, your roof will begin to collect water and could potentially cause leaks in your building. A routine inspection is one of the best ways to insure your drainage systems are up to par.


Flashing Damage or Failure


A flashing is a section of metal used to seal the joints between different parts of your roof like chimneys and skylights. These seals make these specific areas more watertight. If your flashing becomes damaged or fails, water will begin to enter and will cause leaks throughout your building. This is another issue that can be prevented by scheduling your routine inspections.



The cost of maintaining and keeping up your roof will always be less than the cost of repairing or replacing it. You now know the causes of commercial roof leaks, use this knowledge to keep and eye on your roof and extend its lifespan!