Roof Leak or Condensation: What Should a Building Owner Document?

What to Document

Note when water appears — during every rain, only during wind-driven rain, or on clear days. Record whether the HVAC system is running when water appears. Note whether the same area has been patched before and whether the stain has moved over time. Photograph what is safely visible from inside the building without climbing onto the roof.

• Timing: every rain, wind-driven only, or clear days?
• HVAC operation at the time water appears
• Whether the same area has been patched before
• Whether the stain or drip has moved over time
• Safe interior photographs (do not climb onto the roof)

Leak vs. Condensation

A roof leak typically correlates with rainfall — water appears during or shortly after rain, often wind-driven. Condensation often appears on clear days when the HVAC is running and the interior air is humid, or when warm moist air meets a cold surface. Both can produce ceiling stains. A documented evaluation helps distinguish the two and determines whether further investigation is needed.

• Roof leak: correlates with rainfall, often wind-driven
• Condensation: often on clear days, related to HVAC and humidity
• Both can cause ceiling stains — the evaluation helps distinguish them
• HVAC condensate, plumbing, or building conditions may require separate investigation

What Not to Do

Do not climb onto the roof to investigate — roof access should be left to professionals with the proper equipment and fall protection. Do not assume the stain is directly below the entry point; water can travel through insulation, along decking, or through wall transitions. Do not rely on remote diagnosis alone — an onsite evaluation is needed to confirm the source.

• Do not climb onto the roof — leave access to professionals
• Do not assume the stain is directly below the roof entry point
• Do not rely on remote diagnosis alone — onsite evaluation confirms the source

Roof Leak or Condensation: What Should a Building Owner Document? — FAQ