The Most Common Causes Of Commercial Roof Leaks

Roof leak

No one wants to see water coming down from a leaky roof. Commercial roof leaks can lead to serious property damage. If you’re wondering why commercial roofs leak, you should be aware of the most common causes.

Poor Drainage or No Drainage

Normally, your roof can handle the buildup of rainwater through gutters and downspouts placed around the edges. Even so, these systems can be overwhelmed by excessive rainfall or debris blocking them. When that happens, water starts to accumulate on the roof, leading to leaks. If left untreated, the weight of these puddles can even lead to cave-ins, which can lead to significant amounts of property damage and even personal injuries. As long as you have a professional come in to do a routine roof inspection regularly, this shouldn’t be a problem.

Too Much Traffic

There’s nothing wrong with a small number of people on your roof if you have walk pads protecting it. If foot traffic is too heavy, however, then it will start to damage the membrane, which is what the waterproofing layer is called. This is also true of any kind of traffic on surfaces without walk pads. Indeed, the biggest offenders are often HVAC service technicians unintentionally dropping their tools or placing their equipment on the unpadded membrane surrounding the unit. These small cuts and dents can lead to serious damage over time.


Penetrations and Exposed Seams

Every commercial roof will have penetrations for things like vents, drains, the HVAC units or pipes. Although these penetrations are sealed up, you’ll still get leaks sometimes due to conduit so close together that individual flashing is impossible. Screws can pull out, gaskets and washers can dry rot away, and leaks can result. In the same way, your roof’s seams can delaminate over time due to the adhesive failing. This is more likely to occur on the roof’s edges.


Old Age

The average commercial roof is designed to last up to 20 years maximum. Beyond that time, regular maintenance can give your roof a few extra years, but it will soon start to show its age via leaks. In time, these small issues can make a big dent on your bottom line.



In this part of the country, torrential rainfall can be common in the summer, and this can lead to ponding, even with proper drainage. High winds caused by hurricanes or tornadoes can blow a roof off in one swoop or bring tree branches and other types of debris at incredible speeds. The hot sun can also cause damage over time, as can hail.


Human Error

Many business owners go for the cheap option when installing a roof in the first place. This mistake often leads to faulty seaming, poor sealing or improper installations, all of which can lead to significant roof leaks in a relatively short amount of time.


Wall or Masonry Cracks

Although this isn’t specifically a roof leak, these kinds of cracks can appear to cause such a leak if they appear above the roofline. These can be very hard to diagnose, and many business owners won’t believe that the roof isn’t the problem.

Although there are some leaks that can’t be attributed to these major causes, most of them can be traced to one or more. If you have a roof leak, you should relocate any vulnerable inventory and equipment in your building and on the roof itself. You should also note the exact location of the leak or leaks and contact a commercial roofing professional to fix the problem as soon as possible.

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