Chicago people, what's the rough cost of finishing an attic?

[Bradley Koerner]

Space is about 800 square feet, duplex up from the second floor. It has already been dormered and ceilings/walls insulated. Two stair cases already in place. Would need to add a few walls to create 2 bedrooms and build a budget bathroom. Needs flooring. I don't need walls painted (wife and I love painting).

I know this is a very open-ended question, just looking to get a ballpark. Am I looking at like $40k or more like over $100k?

Or anyone have a GC in the area that they'd recommend that I can chat with?

[Crystal Smith]

Quote from @Daniel C.:

@Crystal Smith Thanks for confirming! I have a similar building to the OP where I have an attic with enough space for duplex up or add third unit as part of the ADU ordinance and doing some initial investigation if either option is worth it in terms of the cost/work involved

Assuming the work to run the new water line is another 20 - 40k from a few older comments on BP I remember reading through? I think one person had called out what side of the street you were on would dictate a portion of the cost because it would be significantly more expensive if you had to dig up and replace that as well.

The water line in the basement is about in the middle of the lot, not sure if that varies much across Chicago properties and some come in through the front of the basement/building

We budget $15K for planning purposes.