Help!

[Ganzorig Sharav]

I`m buying three flat in Chicago area. it needs gut job, new wiring, plumbing, central air and unfinished attic. Also I`m adding extra bedroom on 1st floor. Couple General Contractors said I need floor plan, blue print, and permit from City of Chicago. I want everything to be up to date or code. Anyone knows good architecture for residential building blue print? Or should I just do  it without blue print and permit.

Please I need your expertise and advise.