Flat roof to sloped roof joint

[stuartturbo]

Just planning the dormer joint to pitched roof.
I will be using the "rubber" system. Can the flat roof join i immediately below the ridge tile. Or must there be a tile before the flat roof???

 

[tony1851]

What matters at the ridge is maintaing cross-ventilation. Assuming there is a sufficient air gap above the insulation in your flat roof, you need to ensure that this can vent to the outside , as well as venting the front slope. The easiest way to do this is to use the rollout Marley 'Ridgefast' system, which goes underneath your ridge tiles and is unobtrusive.
If you can leave one tile in, it will make fitting of the system easier.