Theory 38/Building Physics
Moisture Risk Is a Vapour Ratio
The claim
Interstitial condensation risk is set by the ratio of vapour resistance on the cold side to drying capacity, not by indoor humidity alone.
01Mechanism
Vapour diffuses toward the cold side and condenses where it reaches dew point; whether it accumulates depends on how fast it can dry back.
02Predictions
- P1Risk should track the ratio.
- P2Humidity alone should mispredict.
03Refutation
Risk tracking humidity would remove the drying term.