When we come across one like this we call it a rug. The homeowner told me that she has not had the roof cleaned as long as she has lived there.
Although it is not very large the possibility for a plant disaster was screaming at me during the estimate. She had a few burns here and there but I informed her of the side effects and she was very happy with her service.
We get a lot of white tile roof cleaning in Tampa especially close to the beaches. If the wind is not blowing your mix over to the neighbors yard the tiles are so dirty you usually have to hit them many times. Plants are my main concern with white tiles, I almost wanted to pressure wash this roof.
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"A people that value its privileges above its principles soon loses both"
we had an entire project that had the funk so thick on them that you could scrape the roof with a quarter and the algae would roll up in front of the quarter. Here are a few before and after pix. These were from 1996.
Please do not use these pix unless you are a PBG Compass Rose member.
AC
-- Edited by AC Lockyer on Friday 8th of July 2011 11:15:40 AM
-- Edited by AC Lockyer on Friday 8th of July 2011 11:16:01 AM
-- Edited by AC Lockyer on Friday 8th of July 2011 11:20:05 AM
Funny thing was a hard freeze came through a few days later and blasted everything. The landscapers pruned and hauled everything away. (including our chem damage) and no one knew the diff. Some of our competitors over the years pointed out the plants being dead in the after pic. I carried around a pic of the court yards showing those dead plants were 15 feet out from the roof line. Still the best before and after pix we ever got!