Chicago Bulk and Density Standards

[Jack Smith]

I have a question regarding bulk and density standards of business and commercial zones in Chicago. Specifically, a lot zoned B3-2. In this case, a minimum lot area of 1000 square feet is required per each unit. This is pretty straightforward, but if someone was to build residential units above the ground floor retail unit (permitted; and no ground floor residential units are permitted in the B3 designation), would the retail unit on the ground floor count as a unit when considering the minimum lot area per unit rule? If that is confusing, would a 2,500 square foot lot zoned B3-2 (community shopping district) be restricted to one ground floor commercial space and one upper floor residential unit, or could a developer build two residential units? I can't seem to find anything specific to this in the Building Code (See Chapter 17-3 for further reference on bulk and density standards in business and commercial districts). Thanks anyone for your help.

Jack