Direct answer
Document the first location, trigger, date, operating state and one unaffected comparison before cleaning or changing anything. That preserves the evidence needed to test Corners and thermal bridges later.
Why this question matters for Corners and thermal bridges
How geometry and conductive framing lower local surface temperature at corners and junctions. In the wider path, the observed clue is water beads, frost or dampness on a cold interior surface A good answer stays tied to the actual sequence instead of converting a familiar pattern into a diagnosis.
What to compare
Include windows, wall corners, exterior closets, roof slopes or thermal bridges, nearby systems, recent work and the places where the symptom is absent. The main lookalikes remain high indoor moisture load, weak ventilation, local thermal bridging, air leakage and exterior water entry.
A useful evidence record
Write down the exact location, date and time, weather, equipment or water-use state, recent changes and one unaffected reference. Preserve photos before wiping, opening, repainting, tightening or resetting anything. State uncertainty directly.
How the answer changes the next step
If the result strengthens one pathway and weakens another, continue to the matching safe-check or scope guide. If both explanations remain plausible, repeat under controlled conditions or prepare a professional handoff rather than choosing a repair by guesswork.
Safety boundary
Do not treat persistent wetting, decay, visible electrical damage or extensive material deterioration as ordinary condensation. Correcting humidity does not replace investigation of active leakage. HouseSymptoms provides information and documentation structure; it does not certify a diagnosis or authorize regulated work.
