ADU build in south St. Louis city

[Adam Litton]

Hello BP community! I am a fairly new investor in St. Louis, MO currently doing a house hack on a duplex I purchased in 2019. I am currently weighing options to increase the potential of this property and considering building an ADU where the garage current sits. Looking up and emailing the city on any restrictions.. seems like the process isn't as intense as I was thinking.

Attached is a picture of the duplex and garage in the back to get an idea of the type of home style in the neighborhood. Looking at the numbers this could be a good ROI, and a good alternative project instead of going the traditional route of purchasing an additional investment property with property purchases high right now. Looking at options... I could do a regular rental, move into (rent out my unit),or air B&B.

1. Has anyone in the STL city area done an ADU build, would love to see the results and some of your hurdles you may have come across?
2. Was you budget pretty close or were there some unexpected cash thieves?  What was your final cost?
3. What steps did you take to get your project moving?   
4. Financing considerations?  

Even though I am looking to see projects in STL I would also love to see and hear about other ADU projects in other areas of the country.

Thank you!