I have been struggling with removing black streaks from brick on an industrial building. I have tried 25% SH (10%), 75% water and a touch of ZEP industrial degreaser applied with a roof wash system. I let it dwell for 30 min and it fully dried. I rinsed the area with a 2nd story tip and the results were not as good as I expected. The area cleaned up about 70%. Does anyone have any advise on a solution that could clean these trouble spots. This is a big 7 building industrial park with the potential for more big commercial jobs.
Attached is a photo of an untreated black streak.
Thanks.
You probably just need a stronger mix.
Agreed. I washed a building for a large company the other day that had this exact problem on their brick. A 50:50 mix applied directly did the trick.
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I’ve applied straight 8.25% to mildew and algae on brick with no problems and it takes care of it immediately. Used a pump sprayer to spot clean a Dairy Queen in BFE. Finished in 45 minutes, got my $400 check, and left for home.
Thanks for the input folks!!! I will revisit it and shoot it with a hotter solution.
I appreciate the feedback.
