I have been searching the net for some answers to a couple of questions that I had about insulating my attached garage. Here is what I have going on. I have a house that the garage has been built and attached after the house was built, so the attics do not connect. I recently decided that i would be nice to have a warm place to tinker in the winter time so I have started in on the project. So far I put R-13 craft faced in the walls then put a 6 mill plastic vapor over that, then sheeted over the top of all of it with 3/8 bc plywood. Now that the walls are all done I have started on the ceiling. My rafters are on 24'' centers and i got a good buy on some R-13 craft faced insulation 23'' wide. My intention is to do the ceiling the same as I did the walls with the insulation then the 6 mill plastic to keep down any wind that may find its way through the cracks then the plywood, I may at a later date blow more insulation on top of the roll-in to get more R-value. I live in west central IL in the country and have no building code out here as fare as having to comply with anything. Dose this process sound ok to you? Is there any thing that you would suggests to do different? Also will it condensate between the plastic and the wood and rot out the sheeting in the ceiling over time? Any help would be appreciated there's not many people that do insulation around here to ask.