Warm humid outdoor air enters and reaches surfaces cooled by ground contact or air conditioning.
Failure path
- Step 1: Outdoor dew point rises.
- Step 2: Humid air enters the crawl space.
- Step 3: Ground and ducts keep surfaces cool.
- Step 4: Moisture condenses on wood, metal or insulation.
- Step 5: Odor and corrosion develop over repeated cycles.
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.
