Pressure washing can damage your composition roof and it takes a lot of precious time. See the improvement after applying 30 SECONDS Outdoor Cleaner to this composition roof.
The process is easy, faster and gentler. Start with 30 SECONDS Outdoor Cleaner, Concentrate. Mix it 1 to 1 with water in a pump up sprayer, or back pack sprayer. Apply the cleaner when your roof is DRY, preferably in the morning, or when its cooler, so the cleaner doesn't just evaporate away.
Saturate the area, paying special attention to the overlapping shingles. The stuff on your roof can really have a strong foothold in the overlapping seams. Once you saturate well, you will start to see the cleaner go white and bubbly and the stuff you are cleaning off, will start to look brown. This is your clue that you have applied enough cleaner and you can continue onto the next section.
Once you are happy that its visually clean then its time to simply rinse with a garden hose. This will leave you a nice clean roof. Now I must admit, some customers don't want to rinse the area. Maybe its too steep, or they just don't want to hassle. This is totally fine. Leaving the cleaner there to be rinsed off by the rain, will not harm your roof. The down side to this, is that the gunk you are wanting to clean off, will look brown and ugly for awhile, until the rain cleans it away for you. If that doesn't bother you, then you can certainly apply 30 SECONDS Outdoor Cleaner, ensuring very good saturation and then call it good.
This advice will work on virtually any type of roofing; composite, cedar or tile. Effective saturation and timing is always key.