Cleaning Black Spots on a shingled roof ?

[JohnB]

What Can I use to clean this shingled roof to get the stains off of it.. I tried Bleach , Hot water , Scared to put caustic on it .. any Idea.

 

[Henry Bockman]

It's hard to tell from the picture but try pool bleach. Just do it at night so it doesn't drip on the customers. Put it on and let it dwell for 10 minutes and rinse.

 

[Squirtgun]

John,
I agree with Henry it looks like chlorine will do the trick. These are picks of a house we did last week using chlorine with a garden hose rinse.

 

[JohnB]

Nice Work SquirtGun ... I think I am going to go to my aunt's this weeked .. She has a Pool.. I know she probably has pool bleach in the pump house somewhere.. I will give it a shot .. I think what has happened to the burger king store is that they hired someone to clean the rubber roof on the top of the building and grease and stuff was washed down on to the shingles and not rinsed off.. This would have had to happen about 1 year ago .. Because since then I have been doing most of the hood cleanings and concrete cleanings as well.

AnyHoo I will give the pool Bleach a shot...

Thanks for the advice....

 

[Squirtgun]

John,
If there is grease on the shingles you can use a sodium hydroxide based cleaner.You have to be detailed in the rinse (i.e. every square inch with no more that 500psi. There are numerous roof cleaners on the market that contain Sodium hydroxide,I prefer the spped and easy of chlorine,but it will not have any effect on the grease.
Judging by the pics you posted most of the work can be done with and extention wand.