When there is a lot of moisture accumulating on your roof, and it does not get cleaned very often, algae would grow a lot faster there. Small portions of algae could efficiently be dealt with using some soap and water, but if there is too much on your roof, it could risk the roof’s integrity and reduce its lifespan. This is why if you notice a lot of algae growing on your top, you should seek a roofing company for professional help with the problem.