What is the best way to insulate an attic, ceiling or rafters?
I would like to know this because my attic is actually built to be a 3rd floor, unfinished currently but roughed in. So, I currently have R19, now I want to add R30 to the rafters which are 2x10's. This will create an insulation barrier of R19, than a huge air gap which will eventually be living area, then R30 above. Is this setup as good as someone just taking R30 and adding it on top of R19?