We use non aggressive cleaning methods on roofs that have moss, algae and lichen problems. We manually scrape the roof and apply a Biocidal treatment to kill all remaining spores and clean your roof. This gives a cleaning effect for up to a year which results in a cleaner roof for much longer In some cases we clean with our steam cleaning equipment. Roofing manufacturers such as Tegral and Marley do not advise powerwashing which can cause damage to your roof. It also just spreads the spores and regrowth will be seen within the year.