Cost to update a brownstone in Boston

[Alan M.]

Does anyone have a sense of what it cost to update (not gut) a multi-family that's based in a brownstone in downtown Boston?

3 units, about 2,000 square feet each. 3 beds, 1.5 bath...potential to make it 4 beds and 2.5 baths as part of the update. Basement is 2,000 square feet and unfinished as well. Kitchen and bathrooms are dated. Windows are reasonably new. Rough is new. 

Thinking about adding a roof deck, updating the kitchen and bathrooms, redoing the floors, painting, etc.