You can pressure wash both shingle and metal roofs. Shingle Roof: When it comes to pressure washing a shingle roof, you won’t be able to effectively clean off all the organic growth. The root of the growth could be coming from underneath the shingles and within a few months, your roof will have growth happening all over again. Not to mention, using high pressure to clean a shingle roof can cause tears and strip the granules of the shingles. Because of this you will damage the shingle and expose it to the elements, thus further shortening the lifespan of your shingle roof. Metal Roof: You can pressure wash a metal roof, but it can be difficult and dangerous because when a metal roof gets wet, it’s easy to slip. Even at a slight pitch, standing on a wet metal roof can cause you to slip off.  Not a lot of metal roofs are flat and many have a high pitch. For pressure washing to be effective you need to be in a close contact with the surface. There is no way to get close without getting on the roof and with a high pitch metal roof that’s wet, it may not be a wise decision. Our Recommendation: It’s better to effectively and efficiently utilize a roof cleaning system that’s not only is handled by professionals, but also gets your roof completely clean and looking new without the headaches, damages, or injuries.