Attach 2x ledger to masonry either with Titen screws, or adhesive screw (with screen tube). Then you just use a top flange hangers and the plywood will go over the ledger. When you frame parallel to the masonry wall, put a ledger also and put blocking every 2 ft and the plywood should go over the ledger. Good luck.
Agree with Mike, so use a strap (Simpson) to attach to blocking where the joists are parallel to the wall. Where they are perpendicular to the wall, strap to the joists.
COEngineer,
I understand why, but where does the code (IBC or referenced) require you to use a treated ledger. The only thing I have found is if the ground is within 8", than it needs to be treated (2304.11.2.2)
tadeng, Yes that how I read it also. I was just pointing out all the requirements for PT lumber as I have found it in the IBC. Now some building departments are requiring PT lumber at ground floor sill plates at all exterior walls, some for all sill plates in contact will concrete. There have been talk also of requiring the first floor studs to be PT lumber due to termites.