Ok guys, I think I should be fine but please share any advice. My current project is a vaulted ceiling. I have a bearing wall that splits the house in half(single story, 10/ 12 roof pitch), 15 foot rooms, each side of the ceiling joists land on the top plate of bearing wall.  For sake of arguement, well just refer to each side as left room and right room. Left room is being vaulted, right room remains 8 footer. Customer wants left room to expand approx. 3 feet into right room with new 2×6 double top plated bearing wall. I plan on Throwing up this wall first and then removing old 2×4 bearing wall and yanking  the left rooms ceiling joists. Of course before I do that, I want to make sure the roof doesnt decide to kill me. Currently, in the attic, I see 2×8 rafters, no purlins, no rat runs, and 2×6 collar ties on every rafter span. To make the vault, I plan on running 2×8 collar ties(these will be the new ceiling) approx two feet below each existing collar tie, rafter to rafter, every span. A 5 foot knee wall will attach from top of new 2×6 bearing wall to the rafters(right rooms rafters) to complete the vaulting of the left room. First off, does this make sense? second, the existing collar ties and new vaulted ceiling collar ties/ceiling joists should take care of lateral spread right? And third, do I need a ridge beam? i hope not cuz the run is about 32 feet. Any thing missing in my calculations or any additional roof support needed?Thanks in advance y’all.