Absolutely! Our service is covered by our 100% satisfaction guarantee. Your roof will look drastically better with proven same day results. Some heavier growths, such as lichen and moss will be killed the day of treatment but may take a while to release their grip on the shingles with a bit of time and a few rains. If you are unhappy with the cleaning results on your roof, we will return and retreat the areas in question at no charge to you.