You probably solved the issue already, but if not and from my understanding we talk about the rear patio.

My guess is this labor is not shown in R&M cost, which was just listed as a flat 5%.Plumbing is a mix of original galvanized and cast iron, and replacement plastic.  

I know this not acceptable so I am thinking I need to remove the debris, spray for mold, paint with mold resultant paint on the joint beams to be safe, lay insulation plastic over the dirt.

A couple of hours later my thermostat started smoking and burnt up melting the plastic and leaving a mark on the wall.

I don't trust to give the code to a prospective tenant; even if we install one with unique codes, you still have to worry about them messing the house, or leaving the patio door open or window open and coming at night to steal stuff, and you'll have no idea which one of the visitors is at fault. 

Bought a foreclosure with a wall that appears to be made up of 2x3 walls sandwiched together with some weird hard plastic membrane between them.

The property complies with the local regulations (self closing gates with locks leading to the backyard, 6ft walls, self closing patio doors to the backyard, etc.

I had to do this twice last month in TN.I had them use trenchless technology where they put in a new pipe in both cases.One was for my personal house $3500 and replaced a pipe that was plastic like and maybe 20 years old. 

If you want to live in the cheapest rent area, look for 4-plex, but once you are there, you don’t want to live there...Gangster, drugs, robbery, break-in...Bikes all the over the places, clothes hanging on the patio for sun drying, very messy look... neighborhood are extremely run down, doesn’t look good at all...After looking at the run down and very ugly 4-plex area, most investors don’t have the appetite to invest there at all...Sorry for the negative comments...But it is the truth feeling...

I arrive & the place is empty except for a couple of plastic patio chairs.