Best Cleaner for Algae on a Roof
The most effective method of cleaning algae and moss from a roof is with a 50:50 mix of laundry strength liquid chlorine bleach and water. Apply with a sprayer and allow the solution to dwell on the roof surface for 15 to 20 minutes, then rinse thoroughly with low pressure water. Use a long-handled soft-bristle scrub brush to remove the moss from the roof, scrubbing from the top down to avoid lifting shingles.
Algae and Moss Removal Process
Signs of an algae infestation include black streaks and stains on the roof. Equally damaging, moss appears as a fuzzy green layer. Both should be promptly removed. Take the following steps:
- Start by cleaning the gutters, as moisture and debris contribute to roof damage.
- Treat the roof with a bleach solution. Mix one part bleach with one part water in a spray bottle. Allow it to soak for 30 minutes before rinsing. Do not use a pressure washer, which can loosen shingles.
- To protect plants, splash them with water or cover with plastic sheeting before applying the bleach solution. When finished cleaning, rinse the sheeting and plants to remove traces of bleach.
- Alternatively, hire a professional roofer to perform a soft roof wash treatment formulated to kill algae and moss without harming pets or landscaping.
Roof Maintenance Recommendations
Asphalt shingles are common roofing types on which algae often grows because they contain limestone, a nutrient source for algae. It is advisable to:
- Clean the gutters to prevent moisture and debris buildup.
- Use a bleach solution for cleaning, avoiding pressure washers.
- Protect plants during the cleaning process.
- Consider professional roof maintenance for effective and eco-friendly cleaning solutions.