Should moss be removed from roof shingles?

Yes, moss should absolutely be removed from roof shingles, as leaving it causes progressive damage that shortens roof lifespan and can lead to leaks. While moss may look green and natural, it is far more damaging than simple black algae streaks. Moss acts like a sponge that holds moisture against the shingle surface for prolonged periods, preventing the roof from drying after rain and accelerating granule loss and asphalt deterioration. Its root-like structures called rhizoids grow under and between shingles, physically lifting shingle tabs, breaking the factory sealant bond, and creating entry points for wind-driven rain and wind uplift. In freezing climates, moss holds water that expands when frozen, further lifting and cracking shingles. Extensive moss can block water flow, causing water to back up under shingles. Removal should be done carefully to avoid causing more damage. Never pressure wash moss off, as it strips granules and voids warranties, and never scrape live moss aggressively, as it will lift shingles. The correct method is to apply a shingle-safe moss killer containing zinc sulfate or potassium salts of fatty acids, such as Moss B Ware or Spray and Forget, allow moss to die and turn brown over several weeks, then gently sweep dead moss off with a soft broom from ridge downward. After removal, install zinc or copper strips near ridge and trim overhanging branches to prevent regrowth.