I just earned a big job for Saturday cleaning windows, gutters and their tin roof where there are some discoloration and mold from being under a tree, etc. I was going to just try and pressure spray but thought it could be a little easier if I applied a safe cleaning solution but I’m foreign to this.
Does anyone have experience in tin roof cleaning and if so do you have any tips or suggested cleaning solutions.?
I have attached a sample of what I’m working with. Thank you for your help!
I bet my friend @TheWindowCleanse could be some help on this one . I dont have any experience with tin roofs 
Search on the pwra forum. I can’t be of much help.
Well thanks for replying so quickly 
You should be able to use SH with a surfactant, apply, dwell and rinse. You can get Sodium hypochlorite at pool supply companies. You will need to dilute it of course, store bought bleach might work, not positive though. You need it strong enough to cut thru the algae, mold and organic matter thats there.
If you use SH, just make sure to spray water on the vegetation below or around the house as a precaution so you don’t burn anything. You should be fine though.
Just FYI, there is another company near me that has brought in some good money by pressure washing roof tops, even shingles. Their work has been looking great and as far as I know they haven’t had any trouble with leaks YET. I’ve been informing any clients who I quote for pressure washing how terrible this is for shingle roof tops. If you don’t have leaks, you are spraying off the top gravel layer which is a UV shield for the shingle. Tin roofs shouldn’t have this issue but I would still be very cautious with a pressure washer in any roof top. With a background in Water Damage Restoration, I can tell you that your wallet and your insurance company would not be happy with you for making that mistake. YouTube has a good load of videos about soft wash roof cleaning, some of them include the previously mentioned solutions. Also, remember safety! I have a rope and harness that I use on any roof that I’m uncomfortable working on. Hope this helps.
@AdamPWC @SimplyCleanKentucky @TheWindowCleanse Thank you for your replies and advice. It’s greatly appreciated. I hope you have a great day!
@HartmannWGC sorry I have seen this post so late. How did the metal roof cleaning go? I have cleaned many of these roofs, and they will end up being more work and time than you think they will.
Oh no problem. It went well but won’t be doing it again for the reasons you mentioned & it’s just slick & dangerous. Hope all is well!