A. While it is possible for you to remove many of the harmful deposits that collect on your roof with a pressure washer, it is very easy to actually do more damage to your roof in the process if you don't know what you're doing. Additionally, it is extremely dangerous to attempt using a pressure washer from a ladder, and isn't something we would recommend to the average homeowner. When you are looking to clean your roof, it is always a more effective and safer option to call in the professionals who can provide you with an effective pressure washing to safely remove those contaminants without causing damage to your home in the process.