Cost of replacing a floor? (not just cosmetic stuff)

I’m wondering what the cost might be for replacing an entire floor, subfloor, and so on for a kitchen in a 100-yr-old house in Bklyn. (This would include removing the subfloor & replacing the ceiling of the basement.) There’s some BAD water damage – washing machine seems to be SINKING into the floor, and kitchen sink has obviously been leaking for oh… say, 20 years? From the basement you can see some major sagging. Area is approx 5ft x 14ft. Anyone had experience doing this type of fix?