The most effective way to remove algae from roof tiles is typically with a bleach solution.
Here's a breakdown of the process:
1. Preparation is Key
- Safety First: Wear appropriate protective gear including eye protection, gloves, and clothing that you don't mind getting bleach on. Protect any plants around the house by covering them with plastic sheeting. Consider informing your neighbors of your plans.
- Weather Conditions: Choose a day that is overcast and not too windy. Direct sunlight can cause the bleach solution to evaporate too quickly, reducing its effectiveness. Wind can cause the solution to drift and potentially harm plants or property.
2. The Cleaning Solution
- Mix the Solution: The recommended mixture is a 50:50 solution of laundry-strength liquid chlorine bleach and water. Mix this in a plastic sprayer. Important: Never mix bleach with ammonia or other cleaning products, as this can create toxic fumes.
3. Application
- Apply Evenly: Using a low-pressure sprayer, apply the solution to the affected roof tiles. Ensure you cover all areas with algae growth.
- Dwell Time: Allow the solution to dwell on the roof surface for 15 to 20 minutes. This allows the bleach to kill the algae. Avoid letting the solution dry completely.
4. Rinsing
- Rinse Thoroughly: After the dwell time, rinse the roof tiles thoroughly with low-pressure water. A garden hose with a spray nozzle is usually sufficient. Avoid using a pressure washer, as it can damage the roof tiles.
5. Post-Cleaning
- Check for Residue: Inspect the roof tiles to ensure all algae and bleach residue has been removed.
- Preventative Measures: Consider applying a zinc sulfate solution after cleaning to help prevent future algae growth. Zinc strips installed near the roof ridge can also inhibit algae growth long-term as rainwater washes zinc ions down the roof.
Important Considerations:
- Roof Material: Always check the manufacturer's recommendations for cleaning your specific type of roof tile, as some materials may be more susceptible to damage from bleach.
- Professional Help: If you are uncomfortable working at heights or dealing with chemicals, consider hiring a professional roof cleaning company. They have the expertise and equipment to safely and effectively clean your roof.
- Environmental Concerns: Be mindful of runoff and avoid allowing the bleach solution to enter waterways. Consider using a more eco-friendly alternative, though bleach is often the most effective.
