Attic frost concentrated around an unsealed access hatch
The frost distribution followed the warm-air leakage plume rather than the roof covering or outdoor wind direction.
✓Measurement Supportedrecorded confirmation level
01 / OBSERVED
→Frost on roof sheathing above the attic hatch
02 / CONFIRMED CAUSE
→Warm indoor air leaking through the attic hatch
03 / REPAIR
→The hatch was weather-stripped, insulated and latched evenly.
04 / VERIFY
No new frost plume formed during a later cold spell.
WHAT CHANGED THE DIRECTION
The evidence that separated the cause
Supporting clues
- Frost plume centered on hatch
- Higher attic humidity after occupancy
- Roof exterior remained intact
Checks performed
- Smoke-pencil test
- Infrared comparison
- Attic humidity log
Field lessonThe shape of frost can map the air pathway.
