Home Soft Wash cleans roofs according to the shingle manufacturer’s recommendations. (Never allow any high-pressure cleaning on your roof, or risk nulling your guarantee from the shingle manufacturer.) To kill the gloeocapsa magma black streaks, moss and lichen, the concentration needs to be higher than a typical house wash solution. Because of the higher concentration, Home Soft Wash pre wets the landscaping, collects any runoff into bags attached to the gutters, covers any sensitive plants and has a team member constantly watering as another team member applies the solution onto the roof. The solution will continue to kill the organic growth for a period of time or until the next rainfall. The black streaks will be eliminated almost immediately, with moss and lichen taking up to 6-8 weeks to naturally dissolve. At Home Soft Wash, we come back in 2-4 weeks to check for any stubborn spots that may need another application, at no charge. We offer a 3-year guarantee, that if any organic growth comes back, we will treat that area free of charge within that 3-year window.