Mildew on roof shindles

I have what appears to be mildew on the roof shingles of my home. Any ideas on how to remove this ?
Thanks in advance......
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Bill Clements wrote:

the mildew/mold......
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On Sunday, June 22, 2003 at 10:39:10 PM UTC-4, jim wrote:

NO NO NO NO NO! thebleach will permanetely damage the shingles!
Leave it be or buy a product specific for the mold.....
roofers can add some metal stips toprevent it from re growing.
its a effect of global warming
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On Friday, May 22, 2015 at 9:29:43 AM UTC-4, bob haller wrote:

You're reviving a 12 year old thread.

GAF, one of the largest manufacturers of shingles, disagrees:
http://blog.gaf.com/spring-roof-clean-up-tips/
"Mold. Discolored streaks on a roof indicate there is mold, algae, or fungu s, which can eat away at the roofing material and, ultimately, cause leaks. A treatment of chlorine bleach or copper sulfate solution applied with a g arden sprayer can kill the mold. GAF manufactures algae-resistant shingles that have a specially formulated granule that inhibits algae growth, in add ition to shingles with StainGuard® Protection. Finally, do not power wash shingles! It can dislodge granules and cause premature shingle failure."
So does the assoc of roofing manufacturers:
http://www.asphaltroofing.org/press-room/press-releases/algae-moss-preventi on-and-cleaning-asphalt-roofing-systems
"The most effective method of cleaning algae and moss from a roof is with a 50:50 mix of laundry strength liquid chlorine bleach and water. Apply with a sprayer and allow the solution to dwell on the roof surface for 15 to 20 minutes, and then rinse thoroughly with low pressure water. "

That's what the sellers of those products want you to believe.

Those would be zinc strips. They work, but are marginally effective. They protect an area about 4 ft below where they are applied.

I suppose it's an immediate threat to our national security, too. Good grief.
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While the thread is very old, the main reason for the growth is the shingles used to have copper and maybe zinc in them. Over the years they cut way back or eliminated the elements that stopped the growth. I just had a roof put on and they have started putting more growth preventive chemicals back into the shingles and have a long warrenty about that growth.
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On 5/22/15 9:29 AM, bob haller wrote:

Many roofers use bleach, but others have stopped because it can discolor shingles and kill plants below the eaves.
Some who have quit bleach swear by washing soda. Others say borax or trisodium phosphate. When I happened to be on my roof, I sprinkled baking soda on the moss, from a can similar to a Parmesan cheese jar. In a few days, the moss was brown.
For a bigger job, I'd use borax in a garden sprayer. The general-purpose solution is 2 tablespoons per quart of water. It dissolves best when heated to about 140 degrees (steaming) on the stove. A bit of detergent could help it soak in.
It would be nice if sprayer manufacturers would publish vertical capability and gallons per minute. My one-gallon sprayer with a hose and wand will spray 10 feet up. My one-hand sprayer will spray 15 feet up.
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I used bleach last summer on camp porch roof to demoss. Worked.
This year I just sprayed some stuff on garage roof. Says it works over time. I'll see.
Greg
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whenever it rains i squeegee my shindles off. no mildew problems.
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Where do you find the time?
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dickhealy wrote:

Next to the rosemary,
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On Sun, 22 Jun 2003 21:10:28 -0500, Bill Clements wrote:

Sounds like your roof has too much shade. Time to get out the Stihl and remove some trees.
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On Friday, May 22, 2015 at 9:12:54 AM UTC-4, snipped-for-privacy@21.oct.2015 wrote:

I'd say it's time to get out the calendar.
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On Sunday, June 22, 2003 at 9:06:37 PM UTC-5, Bill Clements wrote:

Mildew will not affect the shingles protecting your roof.
You must have a lot of rain or a flat roof.
Andy
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On 5/23/15 3:27 AM, Andy wrote:

roofing when the water freezes. I hate it when my shingles come unsealed and the wind blows them away!
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environmentally friendly called called Spray & Forget. Takes a long time to work but it does work.
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On 6/22/2003 10:10 PM, Bill Clements wrote:

A mixture of 50% water and 50% household bleach. Spray it on, set 30 minutes, rinse it off.
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On 6/16/2016 7:10 PM, Chen Cheng wrote:

Killed the OP, wife, and goldfish.
--
.
Christopher A. Young
learn more about Jesus
  Click to see the full signature.
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On Thu, 16 Jun 2016 22:00:20 -0400, Stormin Mormon wrote:

Ha! He's another one answering ancient posts. What's going on lately? Google Gropes, that homeownershub thing, and Mr Chen using the ancient Mozilla 4.73. :-)
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don't blame GG, the post date is prominently displayed.
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On Thursday, June 16, 2016 at 7:10:52 PM UTC-4, Chen Cheng wrote:

that can damage the shingles .......
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