Coach house zoning in Chicago?

Asked by seb koper, Chicago, IL Sun Dec 9, 2012

Hi, does anyone know if a detached coach house counts as a 'flat' in zoning. I have a property in RT4 zone with 2 flats in the main building, and a coach house in the back. I am considering finishing the basement to make it another unit, but does the coach house limit me since it is already considered a 3 flat (the max for RT4 zone)?

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Naaman G. La…, Other Pro, Chicago, IL
Mon Dec 10, 2012
There are a few ways to look at this issue. The coach house should count as a unit if it has a Bedroom, Kitchen and a Bathroom. Coach houses are "grandfathered" in to the Zoning code and its EXTREMELY hard to modfy them AT ALL. Mr. Sachs is correct that you need to perform a Zoning calculation based on your ACTUAL lot size and the size of the buildings you have on the lot. To do this you will need a Plat of Survey.
IF the basement that you are trying to convert into a unit is MORE THAN HALF below grade, then the area of that unit will NOT count against your total Floor Area Ratio. (F.A.R.) If the basement "unit" is more than half ABOVE grade, then the area counts towards the total allowable building area. If you need help performing the Zoning Calculation feel free to contact me.
Good Luck!
0 votes
Erik Sachs, Agent, Chicago, IL
Mon Dec 10, 2012
For RT-4 minimum lot area per dwelling unit is 1000 sf. A standard Chicago lot is 25x125 = 3125 sf. 3125 divided by 1000 = 3.125 which equates to 3 dwelling units (round down). If you have a two flat with a coach house (3 dwelling units) on a standard size Chicago lot you are most likely maxed out on your unit count for RT4. If your lot is larger and allows for additional dwelling units you will still be limited by a handful of other factors.

Call or email me if you have more questions.

Erik Sachs
RpV Realty and Development
Cell 773/368-5515
0 votes
Jack Lewitz, Agent, Lincolnwood, IL
Sun Dec 9, 2012
I believe you are permitted to have 4 units in this zoning class but it is always a good idea to confirm with the zoning book.
0 votes
Thanks Jack - where do I find this zoning book?
Flag Sun Dec 9, 2012
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