Eugene, OR
Heavy moss is removed by hand with soft-bristle brushes and blowers, working with the grain of the roofing so shingles aren't lifted or cracked. A low-pressure soft wash with specialized solutions handles algae, lichen and black streaks without stripping granules. High-pressure washing is avoided entirely on roofs -- it's the method most likely to cause damage.
Brushing and blowing clears the bulk of visible moss without disturbing the shingles underneath, which matters because shingles are designed to overlap, not be forced apart.
Low pressure plus the right cleaning solution removes algae and staining that brushing alone won't touch, without the granule-stripping risk that comes with high-pressure equipment.
