I used 3" plastic-backed batts of pink fiberglass insulation which fit neatly in and around the various contours of the inside of the sections of my roll-up doors. I used a very thin application of silicone caulking around the frames of each section to keep the batts in place by their plastic which was installed facing toward the inside of the garage. When it cured I trimmed the plastic flush with a knive. That alone is perfectly functional and not TOO bad to look at but I still want to put something over this to finish it off better. I was thinking of 1" rigid poly-ethylene or polystyrene foam sheets over to hold the bats flat, protect, and add further R-value, mostly because these sheets are light and I don't want to add to the weight much. I don't know how to calculate the final effective R-Value but if I use some thin self-adhesive strips of foam weather stripping between sections and around the frame of the opening where the door makes contact I should have a fairly warm garage. Comments?