Rotted OSB roof decking. Cold flat roof condensation and through ventilation

New flat roofs that haven't been constructed correctly take about two or three years to start to rot from the inside outwards. The new rear extension on this property is only three years old, and the roof has begun to rot away. The builders didn't construct the roof correctly its not a warm roof or a cold roof but somewhere between and because of the lack of ventilation to voids in the roof and the lack of a proper vapour control layer or VCL moister from inside has condensed to the back of the flat roof decking and this has rotted the bards away.
Humidity levels in houses are getting higher, and the attention to detail on how a flat roof or any roof is constructed is now even more critical. Black mould and fungus soon establishes its and starts the rotting process and as you can see on this video the decking under the roof membrane has completely collapsed. It's only the strength of the roof membrane that is stopping the roof from collapsing.

Видео Rotted OSB roof decking. Cold flat roof condensation and through ventilation канала Steve Roofer