What indicates a roof leak rather than a condensation problem?

Water streaks running down sloped roof surfaces indicate a roof leak rather than a condensation problem. This condition typically arises when water from outside, such as rain or melting snow, infiltrates the roofing system. The presence of consistent water streaks suggests that there is a clear pathway for water to travel, likely due to failures in the roof's waterproofing elements, such as flashing, shingles, or other materials.

On the other hand, condensation problems typically manifest as uniform moisture or stains rather than discrete streaks moving in a downward direction. Uniform water accumulation on the roof surface might suggest drainage issues, but not necessarily a leak. Non-uniform water stains can indicate a leak, but they do not provide the same direct evidence of water movement across surfaces as the streaks do. Presence of rust spots on attic beams could indicate prolonged moisture presence, but doesn't delineate between leakage versus condensation on its own. Thus, water streaks down sloped surfaces are a clear sign of external water intrusion, pointing firmly to a leak.