5 Common Causes of Commercial Roof Leaks

Posted March 01, 2015

With more than 35 years of commercial roof leak repair experience, Bloom Roofing’s technicians have seen just about every cause for leaking roof systems imaginable.

In the guide below, we detail some of the most common causes of commercial roof leaks we’ve found over the years. For any leak or water problem that may cause serious damage to your building, we highly advise property managers to schedule a commercial roof repair from a trusted contractor such as Bloom Roofing.

While problem areas may be identifiable, many leak-prone areas require challenging repairs, and if they’re not done correctly, water problems can often become worse. By scheduling routine commercial roof inspections and keeping a close eye on common problem areas, you’ll be sure to save significant costs with proactive management rather than paying hefty fees for water cleanup and damage repairs.

Below are some of the most common water damage causes that property managers should be aware of:

Ponding Water or Clogged Drainage


If there is no way for your flat roof to drain properly, it may start to look like a swimming pool if your drainage system isn’t fixed quickly. Ponding water can be one of the most common causes for commercial roof leaks or water damage, and can add significant strain to the roofing system as one square foot of ponding water weighs roughly 5 pounds per inch of water.

Between a flat roof’s drains, gutters, scuppers, and downspouts, property managers should ensure that water is properly and freely flowing off of the roof. However, in some instances, the current drainage system may not be properly routing water, which may require commercial roof repairs.

Damaged Perimeter Flashing


Commercial roof leak repair is most often necessary at exterior edges of the roof or at interior parapet walls, where flashings are installed to protect the edges of the roof membrane cover. If flashing is damaged, improperly installed, or becomes loose due to wind or storms, edges of the roof cover are often exposed, allowing moisture and water to seep in to the roofing system and building.

Because roofing systems expand and contract as temperature changes throughout the seasons, flashings often tear or break and can fail the rest of the roofing system deteriorates. Property managers should keep a close eye for damage to flashings as these are some of the most common sources for leaks on flat roofing systems.

Open Roof Penetrations


Penetrations are pipes, drains, and other items that puncture a roof’s membrane. All roof penetrations are prone to leaks and must be secured properly to ensure that the roofing system is protected from water damage.

Roof penetrations can include HVAC units, conduits, vents, drains, pipes, hot stacks, gas lines, or other objects that are routed through the roofing membrane. It’s a good idea to closely observe each and every roof penetration to ensure that they are kept water-tight with flashing, field wraps, rain collars, pipe boots, or pitch pans.

Roofing Membrane Damage


As roofing membrane ages, the material may split, crack, blister, shrink, or puncture, giving way to water and exposing the roof’s insulation beneath the membrane. The roof membrane’s primary function is to prevent water from reaching the building’s interior, making the condition of the membrane vital for preventing commercial roof leaks.


If the roof membrane is visibly damaged on your commercial roofing system, we highly recommend calling a roofing professional immediately to help prevent any additional water damage from occurring. If the problem is caught in time, roofing contractors can often conduct commercial roof repairs rather than having to go with a full-scale replacement.

Age of the Roofing System

At a certain point in time, commercial roofing systems will start to deteriorate beyond the point of repair.Commercial-Roofing-Membrane

Most flat roofing systems start to deteriorate rapidly 15-20 years after installation, though this may depend on the roofing material. Many of the symptoms above may occur at this point, and it may be in a property manager’s best interest to schedule a commercial roof replacement to fix the roof as a whole.

If your commercial roof is experiencing leaks or moisture issues of any kind, it’s in your best interest to contact a commercial roofing contractor as soon as possible. By identifying and fixing the problem earlier on, you’ll be sure to save significantly on the costs of water damage and repairs.

Whether in you’re in need of minor roof repairs or a total commercial roof replacement, Bloom Roofing has experience repairing and replacing thousands of roofing systems. Bloom’s technicians have seen just about every source of commercial roof leak imaginable, and have the knowledge and expertise to ensure that your roof will be water-tight for years to come.

For more information on Bloom’s commercial roof leak repair and roof replacement services, contact Bloom today or fill out our “I Have a Leak” form on our website.