Hi,
I have an a-frame (a triangle) seasonal cottage (a triangle). There is no attic, the walls (which are also the roof) go from the floor right to the peak. If these are sealed with poly and full of batts of insulation, can they not be treated like your standard 8' vertical wall and not require any ventilation?

Thanks
Marty

You should always have some type of insulation in a roof system. If water were to leak into the roof, it would rot the roof since airflow can't evaporate it. You can install insulation baffles and the do what you propose with a ridgevent and underneath soffit type vents. Another alternative I have seen for an A frame was to install 3/4" spacers along the beams, at the roof, staple in black or foam board and the insulate on top of the board. What are you going to cover the insulation with? Don't increase the roof loading with thick plywood or lumber without having a pro look at it.