Moss Treatment is a natural add-on to our Roof Cleaning service. Roof moss will thrive and grow in our damp Northwest climate. It not only looks bad but left untreated can cause serious damage to your roof. We recommend annual roof moss treatment, applied in either a liquid or powder form (depending on the season). This keeps the moss from growing and kills ALL existing spores. This simple and regular maintenance will extend the life of your roof. Our treatment comes with a one year guarantee.