When Shopping Around For A Roof Cleaning Contractor, You Should Be Concerned If They Will Not Tell You What Chemical They Are Using, Or Its Ratio, If Indeed They Do Even Dilute It And If They Do A Thorough low Pressure Rinse that is suggested by The Asphalt Roofing Manufacturers Association. All Tile Roofs Should Not Have Any Type Of High Pressure Used On Them Either, as this can result in damage to the mortared areas.
This bulletin from Asphalt Roofing Manufacturers Association offers concise, easy-to-understand information on common maintenance, repair, installation and weather-related topics affecting both residential and commercial roofs
BEWARE OF "Splash & Dash Companies" and all the "Chlorine Cowboys" calling themselves Roof cleaning contractors that do not rinse the chemicals off the roof before they leave, the concentrated residues that drip from the roof after dew or light rain will kill plants. We have had several customers that in the past had hired one of the above mentioned cleaners. They said they were so surprised after a couple of days that all their plants were wiped out, because during the chemical application the cleaner had covered all their landscaping. "The damage to the plants happened as a result of the chemicals that dripped off the roof several days after the cleaning, because they did not rinse" . Another tell tale sign that they do not rinse is to use a bag on the downspouts to catch the chemical. When they are finished the drip edge around the home is still dirty . Also if you have aluminum gutters, when there is not a thorough rinse done on the roof, what do you think your aluminum gutters will look like in a month or so? I know that sodium Hydrochlorite also known as bleach/chlorine is a corrosive. By the way if you put chlorine on your oil base scalp, what do you think would happen if you did not rinse it out?
