Deck builders encounter houses with sections of cantilevered floor all the time. The interface between the cantilevered floor and the deck ledger must be treated differently than any other ledger connection - directly attaching the ledger to a cantilevered rim joist is a really bad idea. It's no trick to find photos and stories online of decks that collapsed with the ledger still bolted to such rim joists. Most residential floor cantilevers aren't designed to carry any loads beyond those of the floor itself and the outside walls and roof, which bear on the cantilever's rim and the floor joists.