What is a good DIY roof moss cleaner, and should you do it yourself?
Short answer. The most reliable DIY roof moss cleaners are diluted household bleach, oxygen bleach mixed per its package, or a store bought soap based moss killer, applied with a pump sprayer from the eaves. Whether you should do it yourself depends mostly on your roof's pitch and height, because wet, treated shingles are extremely slippery.
DIY cleaner options
- Diluted bleach: kills moss and algae fast; needs plant protection and care around metal.
- Oxygen bleach (sodium percarbonate): mixed from powder per the package; gentler on plants, slower on thick moss.
- Soap based moss killer: potassium salts of fatty acids, sold ready to use; fast on moss, little effect on stains.
- Zinc sulfate granules: sprinkled on moss and activated by rain; slow, but also helps prevent regrowth.
What does not work well
- Pressure washing, which strips granules and can force water under shingles.
- Scraping with metal tools.
- Laundry detergents and dish soaps alone on established moss.
Ask these questions before you DIY
- Is the roof low enough to reach the moss from a ladder at the eave?
- Is the pitch gentle, roughly 4/12 or less, if you must step on it?
- Do you have a stable ladder, a spotter, and soft soled shoes?
- Are the shingles in good shape, or brittle and likely to crack?
If any answer is no, hire it out. Falls from roofs and ladders cause serious injuries every year, and treated shingles are slicker than they look.
DIY tips that protect the roof
- Apply on a dry, calm, cool day.
- Work from the bottom up and never stand on treated areas.
- Remove dead moss downslope only.
See moss and lichen on roofs and the Georgia roof maintenance checklist.