new construction-- how to proceed in the initial stages?

[Melissa B.]

I've found a single family home in a market in Chicago that is definitely on the ups.  The house is a total dump, but the area is perfect (I've researched this area extensively and have been searching for a while) and the property itself is zoned for 4 units. 

There is strong potential for this property, but I need to figure out if it would be profitable for me to pursue.  How can I figure out what it would cost to build a 4 unit building on this land?   Also, who must I meet with in order to ensure that what I want to build is up to code/ legal?  Is there one person I might meet with, that would be able to act as consultant in this process?  If so, how is this person paid/ what is reasonable for them to charge?

Any help the forum might provide would be greatly appreciated-- thank you!

Melissa