Perhaps you are facing a special situation, in which you need to find immediate solutions to clean off your dirty roof. The only problem is, this dirt does not refer merely to debris, branches or dust, but also to more serious threats such as mold, algae, fungi or rust. Pressure washing may seem like a good and quick way to solve your problem. However, you need to make sure that this is, indeed, the answer for your specific situation. Pressure washing can damage the integrity of a roofing system, if applied the wrong way, and should be done by professionals like Mile High Roofing Services.
Pressure washing could also break any kind of bonding used between the shingles. The granules on shingles may also be washed away due to excessive pressure used by this kind of tool. Or it can help spread the moss and mold instead of helping you eliminate it.
The alternative is to use a lower pressure kind of system for your roof. This is also known as soft washing. However, this method can still affect the shingles. Another great idea is to use a special treatment which can ward off any moss, mold, algae etc. from your roof.
At any rate, you can always ask for consultation from the part of a roofing expert who can help you find the best answers.