You need to do some test spots. Any one that tried to answer your questions would just be guessing. Bring some SH and a good degreeser and start testing you need to figure out if it’s organic or some sort of pollutant from what ever that place is used for . Then you can move on to questions
There doesn’t have to be many commercial buildings have blacktop roofs and the walls are the gutters. If that’s the case it’s not organic it’s Tar and you will need a really good degreaser and high pressure to get it off. Heat would be helpful . Again it’s all speculation until you go test it . But first I would make sure any chemicals you use are approved by the company or you may find yourself and the meat processing plant in a world of trouble. This is how national recalls happen
Lets just be real about it. You know just by looking at a job what it will cost you to get it done and how long it will take you to do it. With that being said, If you have been in the game, long enough, you know how to price anything to make money.
So yes, I have tested the stain to determine if my mix will work for the entire job; yes I have my chems in place. I was just checking with this group. Anyone with any connections in this industry can get information, so it is just not that serious for me. I have a vendor that I have used for many year and a working rapport with several others in the industry.
I was merely trying to get some idea of what others thought.
Your worry about the wrong thing in my opinion.
What chemicals did you use ?
How were the results?
How long did it take you to get the area clean that you tested?
How much was the chemical you used and how many square ft does one gallon cover. ? I’ve got about 10 more before I can even come up with a cost to do the job . Then figured out what it’s worth to you and add that on.