ideas for insulating garage/wall ceiling covering

512Stroker,the item about "being glued together" is a thought.I close the service door and it seems the side shakes.
black954,what did you us to fasten the board to the joists?
All these good ideas! I'm gonna need a second job to pay for all this.Bob
Well, because both my rotator cuffs are completely torn, I couldn’t drive nails overhead. So I bought 1” plastic capped nails and removed the caps. Then I had my kids screw 1 1/2” drywall screws into the caps and I just screwed them up to the trusses. It worked great cause I could just jam the screw into the foam board and then screw it in.