Decoding Metal Roof Mysteries: Unraveling the Causes Behind Leaks

Metal roofs, while durable, have their own set of challenges when it comes to preventing leaks and widespread damage. Unlike traditional flat BUR or modified roofs, metal roofs aren’t designed to be waterproof. Instead, they rely on proper water flow, with no allowance for ponding or standing water over an extended period.

Several factors contribute to metal roof leaks:

1. Surface Rust:
   • Rusted metal doesn’t necessarily mean immediate leaks, but unattended rust can peel the coating, leading to holes and scaling. This neglected rust can escalate into major structural damage. Using a rust inhibitor won’t eliminate the rust but can prevent its spread.
2. Deflection:
   • Holes, crimping, or creasing of metal panels, often caused by foot traffic, can result in ponding water, leading to rust and eventual leaks.
3. Movement:
   • A metal roof should have designed movement to allow water to flow off properly. If a repair product lacks proper elongation or flexibility, the panels will continue to move, causing more issues than the original leak.
4. Incompatible Materials:
   • Using specific materials with proper elongation properties is crucial to prevent corrosion and rust. Dissimilar metals can react negatively when in close proximity, leading to further complications.
5. Punctures:
   • Foot traffic or HVAC equipment installation can cause holes, creases, and crimping. For example, dragging HVAC units across the roof can leave a trail of tears and punctures.
6. Fastener Issues:
   • Fasteners with rubber washers, used to attach metal panels, may back out over time, leaving holes or gaps between the metal and the rubber washer. This can expose the roof to water intrusion.
7. Open Laps:
   • Improper installation can result in lifted seams along metal panels, providing openings for water and, ultimately, causing structural damage.
8. Missing Parts:
   • Over time, wind, debris, or deterioration can cause pieces like foam closures, vent flashings, boots, edge metal, gutters, and downspouts to fall off, potentially leading to water intrusion and leaks.

Regular inspection, maintenance, and addressing these issues promptly can significantly extend the life and functionality of a metal roof.

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With 100+ years of commercial roof experience, we’ve seen it all. If you have metal roof leaks at your facility, contact us today!