What Causes Commercial Roof Leaks (And How Coatings Prevent Them)
Commercial roof leaks rarely happen suddenly — they're the result of predictable failure points at seams, penetrations and ponding water that develop over time.
Commercial roof leaks rarely happen suddenly. In most cases, they're the result of predictable failure points that develop over time. Understanding where and why these leaks occur is key to preventing them and avoiding major repairs later on.
The Most Common Source: Seams and Joints
Traditional commercial roofing systems rely heavily on seams. Whether it's TPO, EPDM or built-up roofing, these systems are installed in sections that are joined together.
Over time, seams can:
- Separate due to thermal movement
- Degrade from UV exposure
- Fail under standing water conditions
Once a seam fails, water can enter the system and travel beneath the surface, often spreading far beyond the original entry point. Roof coatings eliminate this issue by creating a seamless membrane across the entire roof — with no seams, one of the most common leak sources is removed.
Rooftop Penetrations and Mechanical Openings
Every commercial roof has penetrations such as vents, HVAC units, drains and piping. These areas are particularly vulnerable because they require flashing and sealing to prevent water intrusion. As materials age, these seals can crack, shrink or pull away from the surface. Even small gaps can allow water to enter.
Fluid-applied coatings conform around these penetrations, sealing irregular shapes and creating a continuous barrier that reduces the risk of localized failure around critical points.
Ponding Water, Drainage Issues & UV Degradation Over Time
Flat and low-slope roofs are especially prone to ponding water. When water sits on the surface for extended periods, it accelerates material breakdown and increases the likelihood of leaks. Standing water adds constant pressure to weak areas, especially seams and flashing points.
Sun exposure is one of the more overlooked causes of roof failure. UV radiation gradually breaks down roofing materials, making them brittle and prone to cracking. Once the surface begins to degrade, it becomes easier for water to penetrate the system.
Certain coating systems, particularly silicone-based coatings, are designed to withstand ponding water without breaking down. Reflective roof coatings also act as a protective barrier against UV rays, slowing the aging process and helping maintain the integrity of the roof.
In Alberta, roofs experience extreme temperature swings. Expansion during the day and contraction at night create constant movement within the roofing system.
Over time, this movement causes:
- Cracks in materials
- Separation at seams
- Stress at connection points
Elastomeric coatings are designed to move with the roof. Their flexibility allows them to expand and contract without cracking, reducing stress on the system.
A Preventive Approach to Roofing
At NFW, we focus on identifying risks before they become failures. As insulation contractors in Red Deer, we provide commercial roof coating systems that protect buildings from the most common sources of leaks, alongside supportive spray foam insulation services.
Once a roof is protected, timing the next recoat matters too — see when to recoat a commercial roof and how we choose between Genyk, Duroflex and other coating systems.
Planning your commercial build? Reach out to NFW across Red Deer and Central Alberta — 403-350-2720.
