I'm needing to rebuild my garage roof. The garage was built in the 30’s/40’s and was stick framed with a 1x8 ridge board, 2x4 rafters, 1x8 collar ties and 1x8’s running across the bottom of the rafters (would that be considered a tie beam or a joist?). I’d like to reframe the roof using the stick method (no trusses) but I’d like to bring the lumber dimensions up to current code sizes. If possible I’d like to skip having the tie beams at the bottom to give me more head room. The garage is 18’4” from wall to wall (square) and has a modified gable style roof (pictures are here) http://picasaweb.google.com/callumh/...84769487257618.
you need that horizontal member that runs between the tops of the walls, if that's what you're asking. it keeps the walls from falling over from the wind or pushing away from each other in the presence of a large roof load (snow)
why are you against trusses? if headroom is a big issue, you can get a scissor truss that will have a pitched top and bottom chord. typically the bottom chord slope is 1/2 of the top chord slope