What should I do if water keeps damaging the bottom of a window frame?

Start by documenting the moisture, not by sanding, painting, or covering the damaged area. First note what you can observe: when the water appears, exactly where it collects, and whether moisture is also visible on the glass or another part of the window.

Condensation on windows can signal high indoor humidity, while leaks and condensation can both contribute to indoor moisture problems. The EPA recommends drying wet surfaces and reducing the moisture source, but its guidance does not diagnose water entering through a particular window. [S1] Record what you see without labeling it a leak or condensation unless an inspection establishes the cause. If it keeps recurring, use the log to request an inspection.

Make a short entry each time you notice moisture. Include the date and approximate time; the room and window location; where water is visible; whether the glass, frame, or nearby surface looks wet; and any change you notice in the finish. If you know relevant context, such as whether you first noticed it after a particular weather event or household activity, record that as context—not as proof of a cause.

Take a photo from a consistent position if practical. Keep the original images together and label them with the date. A photo log is an organizational aid, not a diagnosis or a procedure prescribed by the EPA source. Avoid conclusions such as “failed seal” unless an inspector confirms them. Instead write: “At about [time], droplets were visible along the lower inside edge of the frame; the finish looked darker than in the previous photo.”

You can note patterns, but do not treat a pattern as a confirmed diagnosis. Record whether moisture is visible on the glass, whether it appears only at the frame, and when it shows up. These observations may help a professional assess the situation.

The supplied EPA guidance says window moisture can be condensation and that leaks and condensation can both contribute to moisture problems; it does not give a test for distinguishing them at a particular window. It also cautions against treating surface appearance alone as proof of the cause. [S1] If you cannot tell, write “cause unknown” and ask the inspector to assess both possibilities rather than choosing one yourself.

The EPA advises drying wet surfaces and addressing the moisture source. [S1] You can record that you dried the visible surface and note what happens afterward, but drying alone does not establish or fix the underlying cause. Since the frame is repeatedly getting wet and the finish is changing, arrange an appropriate inspection before cosmetic work hides the area or makes observations harder to compare.

For the appointment, share the dated log and a few representative photos. Ask the professional to inspect the source of the recurring moisture, explain what evidence supports their assessment, and say whether further evaluation is needed. Avoid guessing at a repair from photos alone; this report is meant to organize observations and questions, not prescribe a repair.

Copy and fill in this template:

Window moisture report

• Location: [room and window description]
• First noticed: [date or approximate date]
• Observation entries: [date/time; exact wet area; what else looked wet; finish changes]
• Photos: [file labels and dates]
• Context noticed: [relevant observations, or “none recorded”]
• Steps taken: [for example, “dried visible moisture on [date/time]”]
• Cause: Unknown unless confirmed by an inspection.

Questions for the professional:

1. What possible sources will you assess, including condensation and water entry?
2. What did you observe that supports your assessment, and what remains uncertain?
3. Should I wait on cosmetic repairs or arrange further inspection?

Keep the report factual and add new entries rather than rewriting earlier ones. It gives the professional a clearer timeline without claiming the photo log can establish the cause.