How does water vapour get into the Australian roof cavity?
You will be surprised how permeable walls and ceilings are. And this means that it will let water vapour through the living area envelope and escape into the roof attic.
When water vapour gets into the roof cavity and meets a cold environment, CONDENSATION is the result.
And this is not good for the house or the occupants.
And that is the reason why the National Construction Code is so strict on roof ventilation.
In this Roofing Portal video, we investigate an example of permeability and the ugly results...
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