What proof should I collect before I schedule a building assessment? Use a building-envelope or general building professional when multiple systems, concealed paths or consequential scope decisions overlap.
What to compare
Record the first location, timing, trigger, recent change and an unaffected comparison area. Keep weather, occupancy and system state with every photograph or reading.
What the evidence cannot prove alone
A single reading, image, smell or temporary improvement cannot certify a concealed source. Keep at least two plausible pathways visible until repeatable evidence separates them.
Safe next step
Escalate immediately if safety conditions worsen, an alarm activates, active damage spreads or the required action is outside safe access and competence. Continue with Schedule a building assessment for a bounded action, stop rule and professional handoff route.
