We don’t install zinc strips. Basically, I don’t think they work well enough to justify the cost and I don’t want to sell you something and have you disappointed with the results. This picture pretty much tells the story. Any company selling you a preventative might as well be selling you a bag of beans. Roofs are made to drain anything you put on them. Therefore, any liquid applied to your roof will rinse off almost immediately in the first rain. We guarantee our treatments for two years and tell our customers that they will last between 2 and 5 years, depending on the micro climate of your house.