Your roof can be washed safely from the ground these days without the danger of having people walking around on your shingles risking injury or harm to the shingles with blasting water or boot marks. Your shingles have tiny granules on them that will come off if its power washed. The shingles will dry and curl up much quicker by pressure washing them and not soft washing the shingle. In addition to rinsing all the soap off the roof it is very hard to make the roof look uniform when power washing them. Soft washing the shingles will leave your roof clean for many years. We let our soap sit on your roof and do not rinse it off. All the mold, mildew, moss, lichen and algae will all run off your home when it rains. The mold and moss will dry up and blow off your roof when the wind blows within 2-6 months safely without wrecking your shingles.