I give 5 year pro rated warranties on the work that I do. It is explained to the customer and given to them in writing on the back of their quote. Many of our leaders consider this dishonest but my competitors offer yearly maintenance packages. We all know that roofs do not need to be cleaned yearly. In my opinion that is being dishonest. After 19 years of cleaning roofs, I have never had a warranty claim. Before you offer a 5 year warranty you had better make sure that you have been in business for over 5 years and seen the results or you could set yourself up for a failure. Roofs do not stay clean in certain areas of the country as they do in my area.