Adding basement ADU outside of Chicago pilot zone

[Arthur Chou]

Hey guys, I've been a long time lurker - first time poster. I've been looking to buy a multifamily home in Chicago for the past few months now. I've been going through the motions of assessing properties and I've let a few properties slip through through analysis paralysis! At the same time it's given me a bit more confidence in my ability to find a good deal. I've recently come across a duplex property that seems like a good deal and the basement is unfinished with adequate ceiling height. The issue is that it's outside of the ADU pilot zone. Is it still possible to get a permit to add a basement unit if your property is sitting outside of the ADU pilot zone?

Also, I don't know much about zoning but it's zoned as RT-3.5 which I read is for two flats, SFH, low-density apartment buildings. So I wasn't sure if it allowed for a 3-flat building but I've seen other 3-flat properties in the same zone.

I guess at the very least I'd always have the option to duplex down into the basement instead of converting it into an ADU if the numbers worked out.

Thanks in advance for any help with this!

[Mark Ainley]

@Arthur Chou  welcome to the posting side!  It is very possible to make it into a legal unit but more expensive with more unknowns going into the process.  

@Samuel Pavlovcik might be able to advise you better here and I will also DM you a podcast episode we did with @Samuel Pavlovcik around the topic.   

In your scenario I have always had a duplex down mindset.   

[Samuel Pavlovcik]

@Mark Ainley thanks for the mention

@Arthur Chou in short, there are three potential ways to get this done.

1) The RT-3.5 Zone allows for 1 residential unit for every 1,250 sq.ft. of lot area. This means that if you have a slightly oversized lot at 3,750 sq.ft. you Would be allowed to add a 3rd Unit "By Right" in accordance with the Zoning Ordinances. If you have a standard 25' x 125' lot (3,125 sq.ft.) you would be a bit short...

2) If you are slightly under the required 3,750 sq.ft. and have some uniqueness to the lot, you may be able to obtain a Zoning Variation to reduce the required amount of lot area per unit in order to allow you to add the 3rd unit. That being said, in this case you would need to hire an Attorney and be able to prove a "Hardship" as to why this should be approved. We did just get one of these approved for a project in Pilsen during last months ZBA Hearing; however, that was a unique lot because the rear of the lot was clipped by a diagonal alley...

3) The final option would be to obtain a full-on "Zoning Change" (Zoning Map Amendment) where you would change the Zoning designation of your individual lot from RT-3.5 to something higher like RT-4. The RT-4 designation allows for one unit for every 1,000 sq.ft. of lot area, which means that as long as you have a lot with 3,000 sq.ft. or more, you could add the 3rd unit.

Note: Any ZBA request (Variation or Map Amendment) is not guaranteed. It can also easily take 6+ months to get throught the process, and you would likely needed to have initiated a Zoning Attorney and an Architect prior to the submittal, hence why as @Mark Ainley had noted, many people would commonly opt for the "Duplex Down" option instead, where you dont gain the benefit of a 3rd unit, but you do gain the benefit of adding the additional sq.ft. as part of the 1st floor unit's finished area.

Hope this helps!

[Jonathan Klemm]

First off, congrats for jumping out of the darkness @Arthur Chou!  I've been in your shoes and know that it only gets easier over time so keep on posting more and more.

You've already got some great info above!  I think that you can't go wrong either way when you are getting started, especially if you are looking to house-hack with a low down payment loan.   In my opinion, it's only a matter of time before Chicago allows ADUs everywhere.  

What worked for me was finding a 2 unit in a decent neighborhood where I wanted to live and paying less for my overall mortgage than I would have if I rented in that area.  Happy to dive into more details with you if that would help.