Normal brick washing mix didn’t touch these black stains. Any advice?
Have you tried using SH? A good soft wash mix should remove that pretty easily
5% solution of sodium hypochlorite with surfactant, may need as many as 3 applications. No need to rinse between applications. It WILL disappear, or my name isn’t Mr Sparkle!
Yes, I use SH in my normal solution… even made it hotter and nothing doing…
How strong? Maybe bump up to 50/50 re hit stains multiple times.
Yea, I did that, kept making it hotter and hotter, went over it at least 4 times… stymied.
Are you allowing some dwell time? Let it work, reapply if needed… rinse… Also post treating well help as it dies
Only other guess is that’s it’s oxidation run off from other surfaces… maybe a metal roof?
I see that all the time on flat blacktop roof buildings. A strong degreaser and pressure takes it off
ARe you applying it direct? With a pump up or 12v?
Are you using 12% SH @ 50% with several applications? If you are and still not working check the strength of your SH on something else as it may be weak.
was over 50/50 by the 3rd pass… going to drive by and take a look at it this week and see if it got better.
I will give that a try and see if that gets it.
Used the same solution on a house after this (added more elomonator) and it worked super fast on the gunk, so the solution was good.
So you’re downstreaming a 50/50 solution? Maybe a 1% solution? I believe you need a 4% solution for dirty brick.
Downstreaming? That’s your issue…
Look, if you want to beat this, you will need to follow directions. It doesn’t really matter who’s, but you WILL beat this. Just pick somebody and follow instructions.
I get the impression @florida_condo_cleani may have it nailed. Really looks like it’s coming off the roof.
What is direct downstreaming? Not sure I’ve ever heard that term.