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DDo you have pictures of what your talking about?

Forget about the alcchol it is NOT neede and kills your mix quickly. Also that type of Dawn also has alcohol in it.  Hows fresh is your SH?  If it is somewhat dated, and you mix the alcohol & dawn, you may be down around 3-4%,k and that is weak.  Bump it up to 50-50 and see if that takes care of the problem. You are usuing liquid 12.5 % SH, right?

Roof Cleaning By A&E wrote:

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I just use sh, H2O, roof snot.

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 I use the same, thats all you need. Sometimes you may have to hit a spot a second time.  I understand what he is saying, sometimes on a white roof, you can see a very light haze where the algae may have been.   

yeah i'm using 12.5 sh, how do i know how fresh the sh is? and what do you mean by 50/50
thanks

Zach, sometimes you need to do multiple coats. I've never used tsp. I have had luck using alcohol(only use it occassionally). 50/50 refers to sh and water mix. post some pics

Presidential wrote:

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The mixture i'm using is leaving streaks on the roof and is't has powerful has i thought it would be, any info on why the streaks show up and how do i strength my mixture.. location savannah ga

 

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Almost certainly one of 2 things.

#1. You are killing your SH with the wrong Dawn "It should be old standard Dawn, not Ultra Concentrated" and certainly with the alcohol {Alcohol is a good quick upper for your mix, but only temporarily, then it starts killing the strength. I never bother with alcohol anymore.

#2. You are not keeping the roof evenly wetted and some areas are drying some, without your noticing it?

Most likely #1 though.

All you need is 35% SH [assuming it is bought fresh and is actually 10-12%] and 65% water for shingles [Original Dawn or Ammonyx Lo are good to add for thickness of mix and for helping it stay wet [and a little help with dirt?] 1/2 to 3/4 gallon per 100 gallon mix.

For tile, the SH should be 45-50% and you can add the TSP if you want?

The only time I use TSP anymore, is on really blackened light colored [white] bare tile roofs.

Not much difference in cleaning day one, but if you go back in a week, the roofs done with TSP will be brighter.

If you have a roof with streaks, run back and hit it again, with a mix you know is not compromised. If you want to be safe, just use SH and water alone.

I wouldn't use TSP on shingles and don't get a mix with TSP in it on glass-it etches glass.