First of all, know your metal roof. You should start by doing some product specific research to ensure you don’t damage your metal roof. Second, ensure your own safety. Make all necessary safety arrangements prior to stepping on the roof. Ensure you can reach every part of the roof with ease. If possible, wear a safety belt or harness and tie yourself with a safety rope to a solid & stable structure. Most of today’s prepainted metal roofs only require an annual water rinse with a garden hose.
If your metal roof has accumulated a build-up of organic material you may find it necessary to use a cleaning agent prior to annual water rinsing. There are user friendly products available on the market that you can simply spray on and rinse off. As product availability will differ depending on your location, please check with your metal roof installer or manufacturer for recommendations.
Never use a wire brush, steel wool, sandpaper or any abrasives which will mechanically abrade the surface of your metal roof. If you do not wish to purchase a commercially prepared product, you can create a safe and effective roof cleaning solution at home. Simply make a 5% solution in water with any commonly used commercial detergent. You can use a cloth, sponge or soft bristled brush to apply the solution to your metal roof. This solution should be followed by an adequate rinse of clean water.
For best results, clean your metal roof on a dry cloudy day. If you discover non-water soluble deposits on your metal roof (tar, grease, oil paint, graffiti, etc.), you may attempt removal with careful use of certain solvents, such as mineral spirits or isopropyl. Always follow with a detergent cleaning and rinse.