Moss occurs in all sorts of places, but not all places can be as damaging as moss on your roof. If moss is not dealt with immediately, it can cause structural damage to your house. There have been rumors circulating that you can kill moss directly with laundry detergent. Many people have contested this, saying that the detergent did not work, but maybe the application was not done correctly, and so the moss grew back.
Climb up on the roof and locate all areas of moss.
Use a five-way tool to scrape off as much moss as you can or give the roof a good pressure washing.
Sprinkle laundry detergent on top of mossy areas.
Spray the laundry detergent with water and make sure it is moist but not drenched.
Let sit for no more than 15 minutes.
Pour hot water over the area slowly until all detergent is rinsed away.
Scrub the areas down with a scrub brush to make sure the detergent and moss are gone.