Banish Roof Grime: Easy Steps to Remove Organic Growth from Metal Roofing

Organic growth on prepainted metal roofing can be an eyesore and, if left unchecked, might lead to more serious issues. Thankfully, this toolkit offers a straightforward method to tackle the problem effectively.

Understanding Organic Growth

Organic growth such as mildew, algae, or mold is common, especially on north-facing or shaded roofs. These dark patches are typically not dirt but algae called Gloeocapsa magma, also known as blue-green algae. Although it often starts as small spots, it can spread and cover large areas over time. Algae thrive in humid conditions, feeding off airborne organic material like leaves and bird droppings.

Types of Organic Growth

1. Algae: These airborne plants can spread quickly in humid environments.
2. Moss: Grows in moist, shady areas, thriving on organic debris.
3. Lichen: A symbiotic combination of algae and fungi that can also be mistaken for moss.

Cleaning Your Metal Roof

Regularly rinsing your metal roof with water or a diluted dish soap solution helps reduce organic growth. However, if growth persists, follow these steps:

Cleaning Solution

1. Mix the Solution:
   • 1/3 cup powdered laundry detergent
   • 1 quart bleach (5% solution)
   • 3 quarts water
   • Alternatively, mix 1 box TSP (available at paint stores) in 5 gallons of water for a non-bleach option.
2. Test the Solution:
   • Apply a small amount to an inconspicuous area to ensure it doesn’t damage the roof.
3. Clean the Roof:
   • Spray the solution on the affected area with a garden pump sprayer.
   • Let it sit for 5-10 minutes.
   • Rinse thoroughly with fresh water.
     
     
     

Safety Precautions

1. Personal Protection:
   • Wear protective goggles and gloves.
   • Do not increase the amounts of soap or bleach.
   • Avoid abrasive materials like steel wool or wire brushes.
   • Never use high-pressure washers, paint thinners, solvents, or paint removers.
2. Ladder Safety:
   • Follow proper ladder safety procedures.
   • If unsure about climbing onto your roof, hire a professional.
3. Environmental Care:
   • Cover plants and trees near the roof to protect them from the cleaning solution.
   • Rinse them after cleaning the roof.
4. General Safety:
   • Wear appropriate footwear and clothing.
   • Use fall protection gear.
   • Have someone with you while working on the roof.

Conclusion

Regular maintenance and cleaning of your prepainted metal roof can prevent organic growth from becoming a major problem. By following these simple steps and safety precautions, you can keep your roof looking great and functioning well for years to come.