I still am trying to figure out the roof. I was going to use conventional insulation and drywall for the ceiling, but after all the work and mess doing the walls I have sort of lost my enthusiasm for that. I also am a little nervous about adding all that weight to my roof, with all the drywall it would take to do it. Maybe I'm just being overcautious, but the roof of my old garage was sagging like the back of an old nag in the middle and I don't want to have that ever happen with this new one!
Now I am wondering about just insulating between the trusses. I see plastic or foil wrapped bags of insulation installed between trusses in the ceilings of aircraft hangers and in warehouses, and wonder if there would be something like that available for the spacing of my roof? I don't need the ceiling to look perfect, and distract people's attention from the cars!
The trusses are just 2x6's. Getting the plan for this garage together was a big learning experience for me. If I had it to do over I would have had them use 2x6's instead of 2x4's on the walls, and something a little more substantial for the roof so I could use higher R value insulation.
I was too busy dealing with zoning and codes to leave time to do all my homework I guess. My new garage is literally the maximum allowed height (12' average) and square feet wise (672)for my lot. I found my old garage was too close to the property line so we couldn't reuse the old but good floor for the new one, and after we finally got a plan together and submitted it to the village, they come back with my permit put on hold, because with the garage, "impermeables" covered too large a % of my lot. I ended up having to have some of my driveway ripped out and replaced with lawn at additional cost to comply.
What a PITA, but worth it in the end I guess.