So I have a 2-flat in Little Village and I have a structurally unsound one-car garage that I need torn down and a 2-car put in its place.

I am seriously looking into real estate as a method to build a legacy and long term income for myself as well as my two sisters. 

I would strongly recommend that you instead of starting with a foundation company, have a structural engineer come out and take a look at the property to get a feel for exactly what foundation repairs are needed.You can then have foundation companies bid on the engineer's report to resolve the issues to avoid a situation where you are allowing the foundation company to come up with the estimate themselves as I have heard that foundation companies estimates tend to come in all over the place without an engineer's report to work off and limit their repairs.I will PM you the guy that I used for a property I was looking at recently.   

as I am analyzing houses to buy in cash, fix up and then rent out to use the brrrr method I get the first part of the numbers ran to find the roi is about 10%.

There are two methods of accounting for this. 

You would have to pay down $33,362 to do that, but you could just pay it down over time or just make a mental note of what point you need to refinance once it gets to that level.Just an idea, it may take more time to get positioned for this method, but it will be the best of both worlds... 

Joe Marshall There is a reason you keep hearing about BRRRR is because it is a proven excellent method of investing and building wealth.

This method allows you to get a higher rental rate and alleviates the stress of vacancy. 

Also, make sure your tenant pays online using a recurring payment method [Paypal, bank direct debit, Zenmo, Zelle]. 

If the repairs were done quickly, walls and ceilings open to dry out, there is little chance of mold growth or any structural problem.