Hello, I just about finished insulating the ceiling in my attached garage. To maximize space I installed it directly under the roof sheathing between the rafters (2x6). I used Owens Corning R-19. After doing some research I discovered that it is necessary to have "ventilation space". I live in Portland, OR and generally the temps are pretty mild, no extremes of hot or cold. The garage in not heated nor will it be. There is no living space above the garage and there will not be any sheetroc installed over the insualtion.
The question is do I need to pull it all back out, toss it and go with something thinner? Or, should I be okay?