We’re planning a master bathroom addition in the back of the carport. I plan on hiring out the plumbing work as I don’t want to tackle that myself. Currently for planning what I’m mostly stuck on is the best was to proceed with bringing the floor up to match the house. The carport is sloped toward the driveway for drainage and is roughly 10” below floor level at the highest point. I was thinking either level the slab with concrete to bring the lowest point up to level with the highest point and then building my subfloor on top of that. Or could I do a ledger board along the current exterior wall of the house and build a floating subfloor above the slab?