A bedroom window is wet on the inside during a morning viewing. It is worth noticing, but that single observation does not diagnose the building. The useful next step is to establish where the moisture is, when it appears and what the occupier normally does about it.
Distinguish moisture on a room-facing surface from moisture apparently trapped between panes. Describe what you can actually see instead of immediately labelling it a leak, a failed unit or a ventilation defect.
Ask about the pattern
Does it happen only after a cold night, throughout winter, or after rain? Is it limited to one window? Ask about ordinary heating, cooking, clothes drying and bathroom ventilation, without assuming any answer proves the cause.
Look for associated evidence where access is permitted: stained finishes, damaged seals, peeling paint or a persistent musty smell. Note the weather and time of the visit. A freshly wiped window may tell you less than a candid explanation and dated photographs.
A practical viewing note might say: “Moisture on the inside bottom edge of the north bedroom window at 9 a.m.; seller reports it on cold mornings.” That is more useful to an inspector than “bad windows”.
Separate an observation from a purchase decision
Ask whether there have been investigations, repairs or replacement glazing, and request the relevant records. A promise that opening the window fixes everything is not the same as an assessment of the building’s ventilation and moisture conditions.
Have an appropriately qualified inspector evaluate concerns within the scope of the survey you commission. Make clear which areas could not be accessed and whether specialist follow-up is recommended. Do not dismantle fittings or operate unfamiliar ventilation controls during a viewing without permission.
Finally, connect any proposed remedy to its cause, cost and maintenance needs. Replacing glass, improving extraction and repairing water ingress are different jobs. The point of your notes is to help the right professional distinguish them before you treat a small wet patch as either harmless or catastrophic.