Homeowners of this house contacted Brian C. Jackson, a RCIA certified roof cleaner. The homeowner saw that the black streaks & stains were getting worst and they needed some info on what these were and how to remove them. The house was located in Litchfield NH and the roof was approx 7 yrs old. I informed the homeowner that there roof could be cleaned and should be cleaned as soon as possible because this was an algae and it was feeding in the lime stone filler on the roof shingle. To Find out what this algae is and why it is bad for your roof CLICK HERE.