stucco problem

[patriot pressure washing 14]

im working on a dealership that has stucco along the top, it has heavy black streaks on it that im having problems getting off. ive been shooting 12% with barlox through the xjet and it wont touch it. any suggestions? maybe straight sh like i would be cleaning a roof?

thanks

[premiumpowerwash 14]

What dillution have u been using already? Increase your SHC % and increase your dwell time.

[RSuds 24]

Try Safe Restore if it does not work with the 12% strait. If it is at the top it may be something else that is causing the streaks and it may not be just dirt?

[copgib 15]

I did the Mercury Dealership in Gainesville with the same problem. I had to brush it with straight chlorine with a long extension brush. I did half from the ground and then got on a ladder, got on the roof and brushed the other half. I tried everything at the time and nothing worked like go old brushing straight love! Hugh

[sweetwaterfish 15]

Is it similar to the dark streaks on this column in the foreground? That cap is an EIFS type stucco. It laughed at my regular sauce, even with a 30 minute dwell time. I finally moved up to a 75% mixture applied with a pump up sprayer and 15 minutes dwell.

[RSuds 24]

Looks good. We do a lot of Dryvit up here.