Going to demo old carport attached to house and put garage in. Would like to build up 2-stories for living space above new garage. Rough dimensions 35x30 or so. Will have follow-up questions, but first, what is the standard depth of a garage - i.e. the depth needed to accommodate the length of full-sized vehicles (like Suburban), plus a few feet or whatever so you don't bump the back wall when you pull the vehicle into the garage and you can still close the overhead door? Follow-up questions will deal with best materials for accommodate span requirements. Thanks.

I live in a 50 year old one story home approximately 50 x 25. I am planning on removing the ceiling joists and replacing them with a vaulted ceiling. My roof is a simple rafter gable with a 6/12 pitch. I have a wall which runs down the center of the house, in which the ceiling joists meet and rest on, from both sides. I plan on removing the ceiling joists and extend the center wall upwards approximately 3' and running new joists from each side to create a vaulted ceiling on each side of the center wall. My primary concern and question is how much of the existing ceiling joists can I remove to avoid having the possibility of the roof forcing the exterior walls out and collapsing. Any advice on bracing the roof/walls would be much appreciated.