1. Stop at the safety boundary
Do not inject foam blindly into cavities with wiring, moisture or unknown construction.
2. Capture the baseline
Take one context photo, one close view and a short note describing location, date, weather, recent water use, equipment state and occupancy.
3. Track the trigger
Cold weather, wind and heating cycles.
4. Compare, do not assume
Supports this pathway
- The stripe aligns with framing
- It is stable in calm weather
- Thermal imaging shows a repeated linear pattern
Weakens this pathway
- The cold area changes rapidly with wind
- Air movement is detectable
- Moisture or plumbing explains the location
5. Repeat only safe checks
- Compare calm and windy periods
- Measure surface temperature at fixed points
- Inspect accessible penetrations and trim gaps
6. Decide the next step
If the pattern is active, expanding, safety-related or requires opening inaccessible construction, stop self-help testing and prepare an evidence-based handoff. A building-envelope professional can combine pressure testing and thermal imaging.
7. Verify the outcome
After any action, repeat the same observation under a comparable trigger. A dry surface immediately after work is not sufficient proof when the original symptom was intermittent.
Observe→Compare triggers→Repair source→Verify outcome
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