Structural plan for the new floor

This diagram is the most crucial part of the plan -- and the one that the building inspector is most interested in.

In a nutshell, the plan calls for me to strip off drywall and bolt a 2x12 beam along each side wall.  Then, I will attach Simpson Strong-tie Top-Flange Joist Hangers to these beams on 16" centers.

I will hang 2x12 joists (horizontal brown lines in diagram)  from the hangers, with cross blocking every 48".

One hiccup in the plan: There is an HVAC duct in the existing wall -- I will have to give special treatment to that corner so that the beams and joists hang securely.

Once all the structural members of the subfloor are installed, I must get a "rough-framing inspection" from the Lake Forest building inspector -- then I can install the 3/4" CDX plywood subfloor over the joists and I will have a floor to walk on.

I got this bright idea over the weekend:  Before I finish this floor, I want to get my son, Chris, over to help me lift heavy items like the french doors, plywood, 4'x8' sheets of drywall, etc. up through the floor. It'll be a lot easier than trying to carry that bulky stuff up the twisting staircase.