There are some properties, for instance, zoned to allow two units but haven't been designated a duplex yet.Now, if your place is zoned for single unit (SU), then you have to a primary resident living there to rent out the carriage house/basement apartment/etc.

Heavens only knows the psi that the carriage bolts lived through.There is a solution though; buy a bigger and more expensive toilet.

Or your garage, that used to be a carriage house, sits half on your neighbor's lot.

Currently rehabbing a carriage house that I may turn into an Airbnb in Grove City.

Bought a SFH with a separate carriage house in back then asked the tenant to move out because I had plans to move in and renovate that unit while renting out the SFH.

If those are the current body colors of the house, I'd go with a rich, warm hue for the entry, like a deep burgundy, and unless it has a decided function, remove the glass "storm" door.Find a couple of matching, cool-looking mailboxes and position them together centered under the window.I'd also paint the garage doors a dark gray, about halfway between the siding and roof colors.Replace the carriage fixtures with something clean-lined and contemporary, and much LARGER.Then, do some landscaping... start with about 3-5 junipers or anything that grows tightly (almost straight upward) in a column-like form, plant them in a row along the front of the walkway, maybe with some seasonal color at ground level. 

Automobiles were a new thing, so don't expect a modern 2 car garage.Properties built in the 1960s have machine excavated basements, cinderblock walls and a steel carriage beam.

We also have situations we build additions with a 2 story “breeze way” that falls under the house development standards, but can act as a separate unit from attached carriage house above the garage. 

Hi All,I build here in Indianapolis and have seen the power of adding doors and cash flow via ADU’s (carriage houses) in our market.

I can still buy it as FHA  Its a 4 bed house, with a detached carriage house.