I am in need of some more storage in my garage and have decided it is time to put some attic space up in the garage. When I started to look at what needed to be done, I started second guessing myself about it. The pic below is a cross section of what I have there now. I have rafter ties about 9 ft up from the floor that are 48" o/c with collar ties up toward the peak of the roof that are 32" o/c. What I was initially planning to do was to run a 2X8 16" o/c across the the span at the same height as the 2x6 rafter. I was then going to run 2x6 straps from each end of the collar ties above down to the 2x8s for support. Once i started thinking about how much weight was going to be up there with a 5/8" drywall ceiling and moderate storage above, I started to get a bit worried about doing possible damage to the roof and/or walls. I am in the process of looking for a local architect/engineer to take a look at it but thought I would give it a try here also. Thanks for any responses!