Proceed to install a very heavy rubber mat about 1/2 inch thick, and install plank vinyl on top of it.

Instead of the corrugated pipe, this system used a semicircular chamber that’s 12 inches tall at the center and three feet wide.

If you like living inches from the face of the sun, Phoenix is the place - it's a dry heat. :) I'm a mortgage guy, so you can decide how that informs my opinion.  

I have had some termite trouble so this is forcing the issue and I'd like to fully spray for termites thus the idea to dig out the crawl to 16 inches from soil grade to bottom of joists.

I was in a real estate deal where the seller's broker said the seller wouldn't budge an inch on price or concessions.

I got a hard estimate for 3000 square feet, fortunately it doesn't have flex ducts do they can be scrubbed and mitigated along with every square inch of the house.

So how did every inch get so dirty. 

The water came in under the door and flooded the entire place less then 1 inch throughout the Apartment. 

And there must be one in the basement too.Other things I failed in the past:1)Water heater pressure relief valve must have a metal pipe going to about 3-4 inches from the floor (plastic not acceptable).

Some tenants are like children and pets where they try to take an inch so that eventually they get away with taking a mile; unfortunately for you, you are now seeing this firsthand.