Second Story Cost for 2000 Srq Feet

[Jonathan M.]

So I found a duplex with water views in Florida, where the rents in the area range from $1,400 to $1,600 for a 2 bed 2 bath, the property is zoned commercial. My idea was to build a second story on top of the existing duplex, the second story would have a total of 4 beds and 4 baths making it a Fourplex. Any Idea of what my cost would be everything included?? I just want basic finishings and concrete construction. Thanks