breathable roofing felt and vapour control

[salex]

Hi
I'm building a warm room in the roof and will be using a breathable roofing membrane.
It appears that all breathable roofing membranes require a vapour control barrier on the inside of the insulation, apart from procter roofshield

Are there any other breathable membranes that don't require a vapour control barrier
and could anyone suggest a good vapour control barrier to use

thankss

 

[^woody^]

Polythene

 

[salex]

thanks
I was loooking at dupont airguard but if I can use a sheet DPC then great