I'd like to add a door to the back side of my garage, but since this is a load bearing wall I'll have to brace it temporarily while I frame the opening. The garage has one room above it, which spans about half the depth and the entire width of the garage. I'm not sure of the joist size but the span is 12', and there is a steel I-beam that divides the full 24' span.
Red = 2nd story room
Blue = Garage with nothing above
Rust = I-beam
Brown = Suspected joist location
I'm not sure of the wall construction yet (I haven't opened up the walls yet), but I suspect 2x4 studs at 16" on center. I want to add a 32" or 36" door in the 20' wall under the 2nd floor room, but I'm not sure exactly where just yet.
What type of structure will I need to create, to temporarily brace the ceiling while I cut and frame the rough door opening? How many joists do I have to carry to support the load, and what size vertical members do I need to hold the weight?