A conductive junction and limited air movement create a colder interior surface where moisture can condense.
Failure path
- Step 1: Heat bypasses insulation at a junction.
- Step 2: Furniture or curtains reduce room-air mixing.
- Step 3: Surface temperature drops below nearby surfaces.
- Step 4: Moisture deposits intermittently.
- Step 5: Dust and biological growth mark the repeated wet zone.
What makes this pathway plausible
The timing, location and operating or weather trigger should repeat. A diagram shows a mechanism; evidence from the actual house determines whether it applies.
Best next observation
Record the trigger and compare the nearest materials, components and routes before opening finishes or choosing a repair.
Verification after repair
Recreate the original trigger when safe, then confirm the symptom does not return and affected materials are stable or drying.
Trigger→Pathway→Symptom→Verification
Simulation boundaryThis pathway explains a plausible mechanism. It does not establish that the mechanism is active in a specific house without matching evidence.
