Pressure Washing is always the very cheapest way to get your shingle roof cleaned. A Pressure Cleaner uses only high pressure water to strip the mold from your roof. Unfortunately, your ceramic roofing granules will be removed as well! Because most Pressure Washers work alone, they do not have to pay for a seperate ground person to protect your plants. The high pressure water they use does not kill plants, and it will not kill the plant that is growing on your roof either. It will merely scatter it all over, and it will soon regrow, all over your screen room, house, and neighbors property!
Chemical Roof Cleaning is the way shingle manufacturers want your roof to be cleaned. Any other methos of cleaning will void the warranty on your roof.
Yes, it costs a few dollars more, but it is well worth it.
We have been chemically cleaning roofs here in the Tampa Florida area nearly 20 years.