The biggest problem for me has been the things you find out after you demo.  

Legal non conforming generally means its use has to be changed  per town ordinance IF  it needs rehab such as tearing down to the studs, total demo, partial demo, new electrical system etc..  

It was never rehabbed, so I put some hard work into demo and paid a contractor to rebuild it.

I did all of the demo myself immediately after buying, and I lived in a construction zone for an entire year (one working toilet, no stove, no fridge, no flooring, no furniture, no cable, no TV, no internet).

@Lamont MarableInterior work: Frame first floor perimeter walls as needed for open floor plan.Are you saying they will demo the first floor and take out walls?

I can demo IRR until my fingers drop and there will still be people making their counter arguments, whether or not it is true or relevant.Part of that is that the reader's understanding and interpretation of these spreadsheets and the IRR calculation is not fully understood.BUT again.... that's perfectly fine with me!

Closing day comes and I jumped right into demo.

The building inspector told one investor the house has be demolished, no option and another that he would work with the guy to fix it, but with major costs to fix, may be cheaper to demo and start over. 

Seemed more like a full demo project to me.. 

FYI: I was planning on doing the plumbing/Sheetrock/demo myself, but hire a licensed electrician for any electrical work.