In Florida black streaks on asphalt shingles is known as roof algae. It will only get worse if not taken care of. Algae likes to thrive on the north side roofs where the proper amount of shade is present. It feeds on the crushed limestone that is used in asphalt shingles. Rain spreads the algae down the roof causing unsightly black streaks. Eventually, the algae will take over the entire roof. We can kill and remove the algae, using contractor grade cleaners and low pressure, making your roof look new again.