Warm flat roof / timber cavity wall VCL detail

[nghakrmyk]

Hi all - I expect this has already been covered many times, but I'm still left scratching my head at how I can incorporate consistent VCLs across a new loft dormer where a warm flat roof is used alongside timber cavity walls. I can't seem to find much by way of details that show this being achieved.

 

In particular, is the ideal scenario that a VCL for a warm roof, ie above the bottom deck, would join/lap the VCL on the inside of a timber cavity wall? This seems impossible to achieve around ceiling joists.

 

Is the practical alternative that the VCL is just kept internal, i.e., on the warm side of the timber cavity walls and above the roof plasterboard but under the joists? If so, should the bottom deck VCL be removed so as to not trap air between the two?