How do I calculate rafter size with purlin bracing? The total span is ~23' and the purlin bracing is ~9' from one side and ~14' from the other. Is it calculated on total or clear span?
Edit for clarification: It is purlin bracing with a strongback, aka "under-purlin"
I'm trying to obtain a permit to extend my roof line over a room addition and porch. The room already has a roof, but it's a 1/12 slope and prone to leaks. This would bring it up to the ~4/12 pitch of an adjacent addition. I live in the southern part of Zone 2. The only frozen water we see is covered in syrup or in our drinks. The permit office here will accept my sketchup, or even hand drawn, diagrams for a permit. I just have to tell them what size rafter and spacing I plan to use and they will either approve or deny it.