From what I remember it didn't matter what type of material you had it adhere to because when done properly its good to go; its just a matter of doing it properly.As for the contractor you should apologize for pulling his work down (that enough to piss any craftman off even if its wrong) and you need to explain what you need.

@Patrick Hogan In Titusville, the impending “boom” has been “about to come” for a decade.

Apologies- I know it's a lot of info.

Apologies, if my posted tag you multiple times, not sure what I did there and can't seem to delete it

I apologize, I posted the cash invested incorrectly.

I am NOT a plumber at all, but learning so apologize for stupid questions.  

@Robert Dobbs - my apologies, you are correct that the post mentioned those other locations; that’s what happens when skimming ...

As of now, I first make sure there are no big red flags like the neighborhood, school districts, too much repair needed, etc; then I look for the 1% or 2% rule; the 50% rule; try to estimate repair costs/ARV (which is hard for me).I would greatly apricate any feedback, and I apologize if any of this was hard to understand.

should have been more precise my apologies, single family homes to fix and flip!

Hi @Dean Williams, thanks for your thorough explanation and I'm going to apologize ahead of time for being curt.