Roof Discoloration

[WashRite 14]

I have been asked recently if I did roof cleaning. I passed on those jobs but I seem to be getting more and more requests for roofs. I did a search on roof cleaning and found just about everything I needed to know with the exception of discoloration. Most of the homes in my area are asphalt shingles.

I've had another request for roof cleaning but only on two sides. The north and east areas have the algae growth but the other sides do not. Other than the two areas mentioned the roof is very clean.

Will the water to chlorine (10.5%) mixed 50/50 and a cup of TSP applied by x-jetting cause any discoloration to BLACK asphalt shingles?

Will there be a noticeable difference between the two areas cleaned compared to the other two?

Will this mixture work on all colors of asphalt shingles?

The technical bulletin from the Asphalt Shingles Manufacturers Association says some discoloration will likely recur. I am looking for real world applications - People that do this on a daily basis. Thank you in advance for your responses.

[AquaCleanTN 14]

The cleaning of the north and east will remove the stains and bring back roof color to the same as the rest of the house. You would not see any difference unless the other areas are dirty. The SH and TSP will clean any asphalt shingleno matter what color. Your mixture will need to be adjusted to how dirty the roof is 50/50 SH and water with only 1 cup of TSP may be to weak especially if x-jetted. If you are going to do roofs invest in a delavan 5800 pump from Pressure-Tek, 200 ft of 5/8 chem hose, and a hose reel with a good ppoly sprayer to start. To do the best job for roofs from cleaning and protecting you need more TSP and add Borax and polmolive liquid soap to your mix. Look at the threads for "Applesauce" to get the right proportions for the mix and learn more about Borax and TSP.

[squirtgun 122]

Jud,

That mix will not discolor a black roofs.

[WashRite 14]

I just finished reading all 8 pages of the apple sauce thread. I believe I better understand the recipe now and the preferred set-up.

I appreciate your quick response.