A lot of the accessible units i've worked on nearly come down to the inch.

Depending on how bad is the foundation state (how many inches you have to correct), is very possible the sewer line will disconnect/break in the horizontal portions.

@Paul Winka if you give people an inch, they will take a mile.  

I am in the buy and hold space but slowly inching my way into rehabbing and flipping.

They are really small.. only a couple of inches thick.  

Every internal inch counts - make sure you get it right when you are dealing with doorways, cabinetry sizes, etc.

@Jody SperlingI gotta back this train up a bit.This looks like a plywood subfloor that 12-inch peel-and-stick vinyl tile was adhered to, with or without the use of additional resilient flooring adhesive.

You should FIRST take the time to inventory your investment objectives, risk tolerances, resources outside of the $85k (time energy, desire) and then select a couple inches to get smart on BEFORE spending the money.

The water settled at the bottom was like 4 inches deep, green and slimy. 

I am reading your book right now and didn't get too far before I got stuck in the in Ch. 4, Example 3.