My agent said she could oversee the process but will need to charge 10% of the total expenditure of the renovation for that.

Other than that, you'll want to account for water, trash, insurance, common gas, common electric, cleaning and routine maintenance, landscaping, snow shoveling, and of course, like with buying any kind of property, plan ahead for future expenditures.  

6 unit Multi family apartment building Purchase Price $174k Down payment 20% $34,80030 year loan @ 4.75 interest rate 6 units currently rented at $400 each Planning for:1) 10% vacancy 2) 10% maintenance 3) 10% Cap Expenditures 4) 10% Property Management With taxes & insurance and the above expenses, I’m looking at a $390 per month cash flowBad deal?

@Carl FlintI think most simply put, as with any business operation, the more money you have here and now, the better to fund capital expenditures and other operating expenses.

I estimate monthly cash flow as-is to be ~$160, this includes maintenance/repairs, capital expenditures, vacancy & fixed expenses.

During a 24-month period selected by the taxpayer, rehabilitation expenditures must exceed the greater of the adjusted basis of the building and its structural components or $5,000.

You should start by getting estimates from contractors to determine approximate roofing, heating/air, and what other repair costs are going to be, once you have those numbers, that'll make it much easier to make a determination if the after repair value justifies the expenditures....

Vacancy, repairs and capex(capital expenditures).

Plus some larger capital expenditures including replacing galvanized plumbing with PEX (plus individual unit meters) and minor roof repairs.

It is an older building but it has had some recent capX expenditures.