Planning to finish my basement. We have sunken floors on both levels in ranch style home. To go with the floorplan in the basement, I need to raise part of the sunken concrete floor. It's the pink area in the attached photo (in comment below). Don't want to pour concrete. Thinking I can build it like a deck? I need to raise the floor by 10 1/4". Maybe lay down pressure treated 2X4 as base plate on one end and attach ledger board to the raised concrete step on the other end. Then lay 2X8 joists in between using hangers. Other ideas? Want to be Wisconsin code compliant as well.