I currently have a two story living room and would like add a bedroom above the living room. This would now make the living room a one store room and above it would be the new bedroom. My question is can I use a ledger board and bolt it to the exterior walls (inside the house). The ledger board would be connected basically the same way as a deck of a second story. Please offer me help and if this is allowable in New Mexico?
sure, you should be able to do that just fine.
more ideal would probably be to open the wall, bolt the ledger, and then run the joists over the top of it and face nail into the studs too.
but hanging them off the face of the ledger with joist hangers should be perfectly fine.