How to Clean Moss Off Your Roof Safely

Remove moss from your roof using a low-pressure wash or gentle scraping, then apply a moss-killing solution to prevent regrowth. Always work from a stable ladder and avoid walking on wet or steep surfaces.

1. Pick Perfect Conditions. Pick a dry, overcast day with no wind. Wet roofs are slippery and dangerous, while sunny conditions can cause cleaning solutions to dry too quickly. Avoid working during or just after rain, and never attempt this task on icy or frosty surfaces.
2. Anchor Your Ladder Right. Use a sturdy extension ladder positioned at the correct angle (one foot out for every four feet up). Have someone spot you at the base. Wear rubber-soled shoes with good grip, safety glasses, and gloves. If your roof is steep or high, consider using a safety harness or hiring professionals instead.
3. Clear Away Loose Debris. Clear gutters and remove any leaves, twigs, or loose material from the roof surface using a leaf blower or soft brush. This prevents debris from mixing with your cleaning solution and clogging gutters during the moss removal process.
4. Kill the Moss Growth. Spray a mixture of one part bleach to one part water, or use a commercial moss killer, onto the affected areas. Work from bottom to top to prevent solution from running onto clean areas. Let the solution sit for 15-20 minutes to penetrate and kill the moss roots.
5. Scrape Without Damage. Use a soft-bristled brush or plastic scraper to gently work the dead moss loose. Never use a pressure washer on shingles, as it can damage them and force water underneath. Work in small sections and brush downward following the direction of the shingles.
6. Rinse Clean and Clear. Use a garden hose with a spray nozzle to rinse away loosened moss and cleaning solution. Keep water pressure low to avoid damaging shingles or forcing water under them. Work from top to bottom to ensure complete removal of debris.
7. Stop Moss Before It Starts. Consider installing zinc or copper strips near the roof peak. When it rains, these metals release ions that inhibit moss growth. Trim overhanging tree branches to increase sunlight and air circulation, as moss thrives in damp, shaded conditions.