Easy to fix if the foundation for the pier is solid - put a temporary support next to it and rebuild the column, or go to a permanent steel (or 6x6 pressure treated wood, if you prefer) support.

I had the structure raised and removed and don't plan on re-building.  

I am rebuilding my credit but it is going to take a year or so to get it good enough.

However, I have been rather successful in rebuilding my credit after two forclosures, two charged off cards and a defaulted car loan as well as loads of medical collections.

My question is, what is a reasonable rebuild cost for a single family row home in Philadelphia with mid-grade finishes?

Not sure what we are gonna do with it yet but if it's a tear down rezoning it to commercial and reselling it could be better than rebuilding a home.

I have some idle cash and my builder friend wants to rebuild on lot I purchase. 

Same as residential, look at the income it produces and what it is worth, look at comparable sales and look at what it would cost to rebuild it.How to find out what it would rent for?

., we could not rebuild the the apartments without a variance. 

If you're talking about plumbing and electrical it's a completely different ballgame than repainting inside/outside, rebuilding a deck, putting in a new countertop, etc.