What to clean black streaks with?

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  #1  
Old 02-17-19, 04:58 PM
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What to clean black streaks with?

Picture says it all. I have 4 black streaks like this. And they are right into my face, looking out through kitchen window.
What to clean them with?
Climbing up there is out of question. I can get as far as the gutter level. So it needs to be some sort of spray on stuff.
50 yr composite shingle.

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  #2  
Old 02-17-19, 06:28 PM
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Pretty much any kind of siding wash would probably work. Some have bleach or mildewicide... you would douse it with a garden sprayer and then let it soak. Light scrubbing with a brush and extension pole may be needed. Rinsinbwith a garden hose would be best.

I hesitate to recommend a pressure washer... it's a great way to blow the grit right off your shingles if you aren't careful and since you can't get closer than the gutter you would succeed in blowing water right under the shingles and create a leak.
 
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Old 02-17-19, 06:50 PM
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No, we do not pressure wash roofs. We know that. It's likely algae with dirt. Butt ugly.
Scrubbing is sort of not really, roof is very high pitched. I have to hire someone every time something happens there.
I need something that I can spray on and hose off. I've heard about chlorine... not sure how to mix it though..
 
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Old 02-18-19, 07:44 AM
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Main cause, a horrible roof line design.
https://roofrevivers.com/reason-blac...-on-your-roof/
 
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Old 02-18-19, 08:41 AM
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1 cup of trisodium phosphate (available at most hardware stores);
1 gallon of bleach
5 gallons of water


Got it.
 
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Old 02-18-19, 10:55 AM
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You can decrease the percentage of water if needed. It may take multiple applications.
 
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Old 02-18-19, 11:05 AM
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I need something that I can spray on and hose off.

Really don't think it is going to be that simple if you don't scrub it. It's not like washing mud off. I'd set up a ladder with standoffs and use a brush on an extendable paint pole.

Just like spraying something on your car and hosing it off doesn't get it clean either.
 
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Old 02-18-19, 11:09 AM
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...... but you have to be careful scrubbing shingles as there is a fine line between working the detergent in and rubbing the granules off.
 
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Old 02-18-19, 11:19 AM
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... already suggested light scrubbing but I think he is envisioning some sort of magic wand sort of fix.
 
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Old 02-18-19, 11:21 AM
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No, I am simply not envisioning falling down from 2 story height.
 
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Old 02-18-19, 11:22 AM
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If you don't feel comfortable doing it off a ladder set up scaffolding that is fully planked!
 
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Old 02-18-19, 02:02 PM
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If I really didn't want to get up there, I might try getting one of those 20-foot telescoping poles and a brush head for it.

https://www.homedepot.com/p/Unger-8-...2780/203177326

If you can get up to the gutter level, it would probably reach pretty far up the roof from there. Probably can't get a lot of downward pressure for scrubbing, but that might be for the best with asphalt shingle anyway.
 
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Old 02-18-19, 02:59 PM
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Yep, I have similar pole, just from Love's. I even have a proper brush from HD, specifically designed for roofs. I'll be OK with lite scrub. I have good ladder, a Little Gian type of things.
 
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Old 02-19-19, 12:38 AM
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And then pay a roofing company to install copper at the top of each of those runs, as high as they can get. Maybe even a strip slightly lower down too. It will likely cut down greatly on the cleaning requirements.

Good lord, where does all the water go? Between the roof above, those high peaks on the dormers, and the lack of clearance for gutters between them (Is there ANY space between them or is it done like some sort of valley?)...it must be like shooting the rapids during rains? And I understand it does rain occasionally up there?
 
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Old 02-19-19, 09:29 AM
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Rain? Not much. Maybe 3-4 months in a row, no big deal..
Yes, it does have gap between dormers(?) that's why streaks are right there.
It's lesser issue. When it was built, they left large gaps in siding between where roof line meets dormer side wall. Birds figured that out right away and kept nesting inside attic.
No one is going to do any remodeling. I just want to rid of those dark stains so that I do not enjoy the view every time I look out kitchen window.
Otherwise, it's cute ADU.
 
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Old 02-19-19, 09:36 AM
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+1 on the copper (or zinc) strips. Once you get it clean, they are your permanent solution if you don't want to wash it every year.
 
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