Finishing off an open beam ceiling – How to insulate?

Hello,
I have an open beam ceiling that I would like to cover up with drywall. What type of insulation should I use under the drywall if I don’t have the ability to ventilate the cavities? The beams are 2′ on center spacing and are 5.25″ thick. The roof side of the ceiling has about a 3″ foam board insulation.
Thank you,
David
Replies
Well, you can use anything you want UNDER the drywall. And above the drywall it's not a issue of insulation type so much as it is potentially capturing moisture. Might be best to not insulate at all and install a few small vents somewhere.