= 10.8gm-3 represents the magnitude of the difference in vapour concentration

Condensation in buildings occurs whenever warm moist air meets surfaces whose temperatures are at or are below the dew point of the moist air. It is convenient to classify the effects of condensation into two main types: surface, which occurs on the surfaces of the walls, windows, ceilings and floors; and interstitial, which occurs within the structure of a building.