Look for black streaks, green patches, or any discoloration on your shingles. These are usually algae, moss, or lichen growth. Even small spots spread quickly in humid climates like ours. Other signs include shingles that look darker than they should, especially on north-facing slopes that get less direct sunlight. If your roof looks “dirty” or makes your whole house appear run-down, it’s probably time for cleaning. Don’t wait until the growth is thick and established. Early treatment is easier, more effective, and less expensive than dealing with heavy buildup later.