Five Real Causes of Roof Leaks: It's Rarely the Sheet Itself

Before replacing sheets, trace the water path. Most leaks start in detailing and installation sequence.

The most common misunderstanding about leaking color-steel roofs is blaming the sheets. In fact, 90% of leaks trace back to five issues:

1. Ridge caps with insufficient lap or missing closures, letting wind-driven rain push in; 2. screws placed in the valley without sealing washers, or off the purlin; 3. joints between daylighting strips and steel sheets not detailed for thermal movement — expansion tears the sealant; 4. undersized gutters or reverse slopes, so water ponds over the flashing; 5. sloppy flashings around penetrations for fans and ducts.

Prevention lives in design: detail the joints in advance and brief crews on every penetration. For a leaking roof, run a water test to trace the path first — far more effective than patching sheets.