Moss can be physically removed with water and a hard brush on a stick, or with a scrub brush, chemically, or using a little bit of both. When all the moss has visibly turned brown, it is dead and can be removed. This may take a month or more after applying the moss remover. Go up to the roof and start removing the moss, working from the bottom up.
The best tools are a soft-bristled, long-handled scrub brush and a 5-in-1 spatula or painter's tool. Use these tools to gently lift the moss mats and remove them with a brush. At the seams, use the sharp edge of the scraper like a dental pick to push out the moss. Spray-washing moss from the ceiling is the easiest method to get rid of it.
You can prepare a mixture consisting of 50 percent water and 50 percent bleach. Be sure to spray in a downward direction. Liquid moss removers cover the ceiling more evenly than dry powders and allow them to remain on the floor during application. Professional roofers have the tools and training to remove moss from your roof and, in the long run, can save you a lot of money on repairs.
But even in humid climates, roof areas that get even a little intense sunlight every day may not develop moss. Then, use a long-handled, soft-bristled brush to remove moss from the ceiling, rubbing from top to bottom to avoid lifting the shingles. Prevent a moss problem from recurring by installing strips of zinc- or copper-coated sheet metal just below the upper ridge on both sides of the roof. At the end of a session and before taking long breaks, spray the ceiling to move the moss debris into the gutters.
Unfortunately, cleaning the moss off the roof can spread spores that can grow back in the next few weeks, further exacerbating the problem. Usually, moss starts to grow between shingles, as this is where moss colonies start to accumulate. Once moss has adhered to wood shingles, it is much more difficult to remove than from the relatively smoother planes of composite or asphalt shingles. Newer asphalt, fiberglass, or slate shingles may have a chemical coating resistant to moss, but older tile roofs are often invaded by moss or other growths.
So don't be tempted to use a pressure washer or a jet of pressurized water on the ceiling when you remove the moss. If you have a significant portion of moss on your roof, it may have already caused some damage to you. Before using any agent to remove remaining moss, it's a good idea to clean the entire roof of any remaining debris that could protect moss spores. Pressure washing may seem like the easiest solution for removing moss from roof tiles, but it's not ideal.
Dry dust moss removers require you to go to the ceiling and take stock of the moss problem during application. Distribute the moss remover in uninterrupted horizontal lines 2 to 4 feet apart, parallel to the roof ridge.