Find houses that have already sold and compare them to what your place is going to look like when it's done.

Look into Homestead funding and see use them as a baseline to compare with everyone else so you ensure you get the best rates.

A couple of extra points interest on $50k for a few months is peanuts compared to the alternative. 

@Dorian Guin how to the unit costs compare to SFH in the same area (i.e. cost per unit vs. what a SFH costs)  do you have an idea on why the other units have been vacant?

But I don't think comparing renovations to a primary residence and the sort of work you're going to have to do on a defunct 2-4 MF in a slum are two different beasts.

He didn't believe the acquisition price was good enough "per door" (he was comparing it to SFH ratios) to make a profit.

Some key points on the Single-Family segment are:*November '18 sales volume down 2% from Nov '17*November '18 median price up 4.4% to $235,000 (the highest ever for a November on record)*Year to Date, sales volume 4.6% higher compared to 2017's record volume.

As they're demoing the roof (and making a HUGE mess around the property, tar and gravel roof+ pine needles being thrown around the yard with no tarps), he comes back and tells me that spacing between the decking is too far apart compared to code, and it's going to be an extra $3,500 to redeck the entire roof (could have told me this when he gave me the initial quote, wasn't hard to see that).

And if they did sell for those amounts look at the pictures of those houses and compare them to yours.

Do you not check on recently sold comparable properties first?