Once you notice algae on your roof shingles, the next immediate step is to clean it off. Algae may not seem destructive at the beginning but with time it will weaken and completely destroy your roofs.

You can remove the algae with various methods that involve use of various solutions that contain water, bleach and other chemicals. You can also opt to use algae resistant roofing materials. Read on to find out how to clean and more after care ideas.

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Why algae should be cleaned off

Algae grows on most types of roofing materials but mostly on bitumen shingles, concrete and ceramic tile slates or painted metal sheets. It is important to clean algae from your roof due to the consequences that come with it remaining on the roof.

  • Algae cause holes or gaps that lead to leakage causing rotting of the roof. It reduces the quality of your roof making it to look worn out and ugly.
  • As it grows on the roof it loosens granules creating premature granules loss shortening the life of the roof.
  • It similarly peels paint off the roof and causes discoloration.
  • Algae eat away the base of the shingle expanding the contact with the outside temperature.
  • It contains fungus spores that affect people who are allergic to it.
  • If you have a reflective roof the innate solar reflectance is lowered by algae.
  • In addition, some people claim that it has unpleasant smell and it may lead to health problems.

Cleaning Algae off roof shingles

Roof shingles are cleaned with oxygen bleach and water, bleach and water, mixture of trisodium phosphate, bleach and water and finally bleach, powdered laundry detergent and water. Cleaning should be done in the morning hours or evening on a cloudy day because bleach evaporates when there is a lot of heat or the sun.

In all the cleaning processes you require a ladder for climbing the roof, gloves to protect your hands from chemicals, wear a long sleeved shirt and rubber soled shoes that grip the roof. Also wear goggles to protect your eyes from chemicals. You need a garden sprayer for the cleaning solution and a garden hose for rinsing the roof.

Oxygen Bleach and Water

Oxygen bleach is environment friendly thus there is no need of spraying the plants and shrubs around. But it may take longer to clean the algae on the roof shingles. You require oxygen bleach, water, a garden sprayer, ladder, gloves, and rubber soled shoes.

  1. Mix oxygen bleach and water in a garden sprayer depending on the amount of sodium per carbonate.
  2. Pour the solution in a garden sprayer.
  3. Climb the roof using a ladder while carrying the solution.
  4. Spray the shingles affected with algae.
  5. Scrub shingles gently with a brush.
  6. Leave it to soak for 15 minutes.
  7. Rinse the roof with water using a garden hose.
  8. Leave the remains of algae to be swept later by wind or rain water in a few months.

Cleaning with Bleach and water

The mixture of bleach and water is reactive hence you need to take precaution by wearing goggles to protect your eyes and gloves to protect hands from the effect of bleach. You need bleach and water in the ratio of 50:50, a garden sprayer, rubber soled shoes and a ladder. The process is as follows;

  1. Use a ladder to climb and inspect the roof for the parts of the roof shingles affected with algae.
  2. Water plants and shrubs around the home with water to prevent them from the effect of bleach and exterior parts of your home including windows to prevent them from stains.
  3. Wear gloves, goggles and rubber soled shoes.
  4. Mix 50% of bleach and water in a bucket.
  5. Pour the solution in a garden sprayer and climb the roof using a ladder while carrying the solution.
  6. Spray the areas affected with algae.
  7. Leave it to soak for 15 minutes.
  8. Rinse the roof with water using a garden hose.

Bleach, powdered laundry detergent and water.

This method is fast and efficient. You require powdered laundry detergent, bleach, water, garden sprayer, a ladder, gloves, goggles and rubber soled shoes.

  1. Use a ladder to climb and inspect the roof for the parts of the roof shingles affected with algae.
  2. Water the plants and shrubs around the home with water to prevent them from the effect of bleach.
  3. Put on rubber soled shoes, gloves and goggles.
  4. Mix 1 cup of powdered laundry soap, 1 cup of chlorine bleach and 1 gallon of hot water in a bucket.
  5. Pour the solution in a garden sprayer and mix well.
  6. Climb the roof and start at the top of the roof to spray down since spraying up loosen the shingles.
  7. Keep applying the solution on algae as you scrub wet area of shingles with a stiff bristled broom.
  8. Rinse the roof with water using a garden hose.
  9. Repeat the process till when the roof is clean.

Cleaning other roofs

You can use several methods to clean algae from other roofs which include use of trisodium phosphate, bleach and water or preferably use of wet and forget.

Cleaning with a mixture of trisodium phosphate, bleach and water

Trisodium phosphate uses sodium hypochlorite as an active ingredient. You require 1 quarter of bleach, 1 gallon of water and ¼ cup of trisodium phosphate, a pressure washer with a soft spray or a garden hose sprayer, a ladder, gloves, goggles and rubber soled shoes.

  1. Use a ladder to climb and inspect the roof for the parts of the roof shingles affected with algae.
  2. Spray the plants and shrubs around the home with water to prevent them from the effect of bleach.
  3. Put on rubber soled shoes, gloves and goggles.
  4. Mix 1 quarter bleach (6% Sodium Hypochlorite), 1 gallon of water and ¼ cup of trisodium phosphate.
  5. Pour the solution in a garden sprayer and mix well.
  6. Climb the roof and start at the top of the roof to spray down since spraying up loosen the shingles.
  7. Spray on the areas affected with algae
  8. Leave it for 15 minutes to 20 minutes
  9. Rinse the roof with a garden hose, using slow and even strokes.

Cleaning the roof using wet forget

Wet forget is a unique combination of biodegradable selective surfactants for algae, moss, and mildew removal on exterior surfaces. It is diluted with water and applied on the roof affected with algae and works immediately. It is environment friendly hence there is no need of watering plants and shrubs around. Simply spray and walk away. It is non acidic and contains no bleach.

  1. Use a ladder to climb and inspect the roof for the parts of the roof shingles affected with algae.
  2. Dilute wet& forget with water.
  3. Pour the solution in a garden sprayer and mix well.
  4. Climb the roof and start at the top of the roof to spray down since spraying up loosen the shingles.
  5. Spray on the areas affected with algae.
  6. Leave it for a while and repeat the process.
  7. Leave it to be washed away with rain water or for the wind to blow it away.
  8. Do not scrub, rinse or power wash.

The disadvantage of this is that it may take some time to clean all the algae on the roof because you have to wait for rain or wind to blow it away.

Prevention measures to avoid future algae

Annually inspect your roof to discover areas that are affected by algae.

Frequently clean the gutters to remove buildup of dirt, debris, leaves and dust.

To enhance flow of moisture and sunlight, trim tree branches hanging on the roof and similarly improve ventilation for proper aeration.

Also consider algae resistant roofing options like stain guard shingles that have copper containing granules for distribution of copper ions on the roof to prevent growth of algae.

Finally preventing algae from the roof is better than cleaning. Taking action immediately after discovering growth of algae on the roof minimizes the damage that can be caused by algae. Every method used to clean requires careful application to the roof. Frequently cleaning the roof keeps away algae. Consider the roof manufacturer’s instructions and involve a professional when necessary.

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