Exposure to sunlight is the best way to control roof moss.
Moss needs shady, moist conditions to survive, and it quickly dies when the sun’s rays shine on it. However, bleach is a close second. It will effectively kill moss within a matter of hours. And it can help keep moss from growing back. Moss can’t live on inorganic surfaces alone. It needs a thin layer of dirt or other organic material to gain a foothold, and a periodic bleach scrubbing will quickly get rid of that.
- Mix 1/3 bleach with 2/3 water.
- Liberally spray the mixture onto the moss.
- Take care not to scrub with a wet brush – you could easily remove roof granules.
- Let the solution sit for an hour. “Gently” scrub dry mossy area with a soft bristle brush. (If you are cleaning an older roof, skip the brushing, as you will likely lose roofing granules.)
- Rinse the area with water. DO NOT POWER WASH your asphalt roofing shingles.
- Repeat as needed.
- TIP: Wear gloves and old clothes when handling bleach mixture.