Top Plate Isolation Question

This is part of this studio build: viewtopic.php?f=2&t=10633 I plan to add fiberglass insulation between the rafters, then 2 layers of 5/8 sheet rock as my outer leaf in the attic. My concern is the top of the walls, above the top plate. My outer leaf at that point will be the fiberglass and 2 layers of sheet rock. I have to leave an air gap to allow air to flow through the pink rafter mate. My current thought is to stuff this area around the rafter mate with OC 703, or something similar. Is this acceptable? I'm assuming this is one of those things you have to live with, as Rod has mentioned several times in his book, as well as posts on here. Any insight would be helpfull. James

Where does this occur - it doesn't appear to be an eave. A section would help explain the question.

I was thinking about doing the exact same thing except I'm thinking about using the roof as my second leaf, and adding massive layers of insulate right up to the vent in the rafter mate. I don't think there would be an issue filling in the area around the rafter mate, just not in front, because you obviously still need that air flow. I may be wrong here tho. I betcha Brien knows the answer

JK Recording wrote:

My current thought is to stuff this area around the rafter mate with OC 703, or something similar. Is this acceptable? I'm assuming this is one of those things you have to live with, as Rod has mentioned several times in his book, as well as posts on here. Any insight would be helpfull. James

Hi James, long time no see. That really is a good question and I really wish I knew a good answer. The air flow is a given, it has to be there. But as I am seeing this, the air that is needed for the actual sheathing of the roof basically remains unobstructed, yes? I think this is important in so many respects as it pertains to material longevity, thermal control and the like. As this progresses you will have a room in a room type design, with a sealed inner air envelope yes? So that is also good, as we both are aware. Whatever you do in this cavity, if this were me, I would not allow the insulation to restrict any of the air flow area from the porch(is it the porch?) to the rafter to rafter space, and I would also keep an open area from the sheathing downward of at least the height of the venting baffles, more if I could get it. Reasoning is the baffles are more to prevent soffit or overhang from being stopped up with insulation while allowing the owner to make use of the maximum depth of insulation needed to maintain an energy efficient home. They have never been considered a replacement for open air access. Outside of that, you may require someone that can tell you with more authority than I currently possess, me being just some guy on a forum in the construction trade :)