The core idea
Condensation at the room-side edge, between panes and on exterior glass represent different mechanisms.
How the mechanism works
Surface temperature, indoor humidity, glazing seal condition and outdoor radiative cooling create distinct locations.
When it becomes relevant
Typical trigger: Cold nights, high indoor humidity or failed insulated glazing.
Evidence that supports this interpretation
- Room-side water wipes away
- Between-pane fog cannot be wiped
- Exterior dew appears on high-performance glass
Evidence that weakens it
- Rain enters a frame joint
- Only one lower corner wets during storms
- Wall moisture extends beyond the opening
What this concept cannot prove alone
A single observation, image or meter reading cannot confirm the complete failure pathway. Use this concept to form better questions, compare alternatives and decide which safe observation would be most informative next.
Safety and professional boundary
Persistent frame wetting or decay needs envelope assessment even if glass condensation is expected.
Primary references for this topic family
These references ground the general building-science or safety context. They do not diagnose a specific house, replace local requirements or certify a repair.
