RadRemod,
Cleaning roofs in Pennsylvania is a little different than cleaning roofs in the pacific NW. We don't have near the moss problems that you do out there. With that being said, I have never tried to use Tide w/bleach to kill/clean moss from a roof. From my experience, it would not be near strong enough to kill the moss effectively.
When I clean roofs in Pennsylvania, whether they have algae, moss or lichen on them, I use the same cleaning chemicals. My chemicals work very well on all three roof problems. My chemicals kill the moss and after a week or two and a good rain the roof is completely free of the moss. Because we do not scrape or brush the moss there is vitually no granule loss as a result of our cleaning.
Some companies in your neck of the woods use a scrape, air blow and then a zinc powder treatment to clean the roofs, but it DOES remove granules doing it that way.
Moss and lichen really root into the shingles. If you forcefully remove the moss, it will take granule with them. If you kill the moss chemically, the roots will get brittle and come off with the wind and rain.
Here are a couple of pictures of a roof I did in West Chester Pennsylvania that had a lot of moss on the back of the roof and a small amount of moss on the front by the dormers. The pictures of the rear of the roof did not turn out very well because of lighting conditions, but the front pictures turned out pretty well. The moss turns white after you spray it and then comes off after a few weeks or a few rains.
Sorry I rambled on so much. If you would like more information on the chemicals I use, PM me and I will give you more info. I could go on for hours about roof cleaning. I love it! :clap:
Brian
