Here's a qucik mockup of the garage more matching the house.That foundation, wow, what a mess.If it were mine I would have a structural engineer and maybe a soil engineer come out and give an opinion on it.It's sheer weight may have made it crack off like that, no rebar, etc...If it's was salvageable, maybe I would jackhammer away the broken parts and reset the walls on the good part. making the garage smaller.Disassembling and bracing one wall at a time and increasing the overhang of the roof.Then when done, gypsum board the entire thing inside and paint it ceiling white.If it were  my personal garage I would Pink Panther insulate it and use a space heater for winter comfort.It could be a nice little gym for renter who works out.Also, I would have an electrician verify the electrical is hooked up correctly for garage (because the concrete seems amateurish I suspect the electrical may be too).

The other problem is the stats change, I do new soil farming every 6 months to determine changes and recognize changes in my research.  1. reasearch, research, Research your area2. set your criteria, ROI limits, and geo specific areas3. setup auto search systems or notifications4. rinse and repeat : Goto to step one

I was saying virtually no overhead if I'm just providing the soil they are parking on.

If your rentals are in Texas make sure you check out the local soil conditions.. clay and movement of soil is very common in many parts of Texas and its not if  its when your going to need foundation work.. 

@Joe Homs - Thats how anyone sees it by general agreement and thats probably the HOA first response but in this case, firstly I have no idea of this as the base is 100% caulked before I even purchased this, secondly ,if I press the flooring in the bathroom   I see water just pops up ,or  the hardwood flooring in the living room feels like a bit wet underneath, it could have spread to other apartments flooring as well and it could impact the whole building (you won't know until someone opens the flooring) ,want to brainstorm on how to convince HOA to chip in?

Any plating of metals or cleaning materials tend to corrode plumbing drains and leak into soil.

Underneath the picture I have the following "best investments this author has ever made!"

I have 3 little cottages located right underneath Kyle field (.5 miles away from the front door) and am in the works of adding 5 more properties to the STR portfolio.

They attract bugs at night and then mice underneath.

Soil typesNot all dirt or property is worth the same Road access from the highway.