warm deck

[thunderbolt]

Hi folks
Is a warm deck necessary to provide adequate ventilation for a flat roof garage which is being converted into a music room (not accessible from inside the house) ?
If so,can this be achieved without having to build up the roof ?
Really grateful for opinions on this!
cheers

 

[freddiemercurystwin]

A warm roof requires no ventilation gap http://www.delston.co.uk/coldvwarmroof.htm

 

[^woody^]

You can't form a warm deck retrospectively without taking the existing deck off.

If you can't ventilate the roof void, then you will have to completely fill it with insulation, and fit a vapour check barrier or plasterboard. And if the joists are less than 150mm deep, you will probably have to insulate the underside to prevent pattern staining