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How To Remove Algae From Roof Shingles

Cleaning roof shingles is an affordable way to restore your home’s curb appeal, prolong the lifespan of your roof and can be a good idea to improve  the health of your home and family. Cleaning your roof can prevent the need for costly replacement in the years to come because algae, mildew and moss will ultimately damage shingles.

It is not advised to use high powered pressure water to clean shingle roofs because this can dislodge the granules in the shingles and that can lead to high heating and cooling costs and lead to premature failure of your roof.

To clean your asphalt shingle roof you will need a special shingle roof cleaning mixture, a low pressure washer, a pump sprayer or, a ladder to access your roof, personal protective equipment such as rubber-soled shoes, safety glasses and a harness.

The Special Roof Cleaning  mixture is:
4 gallons of water, 1 gallon of bleach and 1 cup of TSP (Tri-Sodium Phosphate-or acceptable phosphate-free
substitute).

Apply this mixture with a garden pump sprayer, let sit on the roof surface
for up to 20 minutes, and rinse with low-pressure water.

Be sure to protect any shrubs below. Remember, the
roof surface will become slippery when wet… be very careful!!!

Algae Staining on Asphalt Shingle Roof Surfaces

What Are Those Black Stains on a Shingled Roof? Those black unsightly stains are algae. Algae appear as dark to black stains each shingle and usually covers a majority of the roof surface area, more predominantly on the lower portion of the roof where moisture content is higher and taper as they reach the ridge caps.
How Does a Roof Get Stained with Black Algae? Algae can spread from one infected roof to another via airborne spores. These spores land randomly on a roof
and take root. A Shingle is the perfect breeding ground for algae due to its porosity and constant moisture content. A protective sheath creates the dark to black color the algae forms in an effort to protect itself from the sun’s UV rays.
How Does Algae Grow? Algae require moisture and proper temperatures to grow. Dew is the primary moisture source. Algae are
found excessively in the Southeast of North America, but it can and will grow anywhere. The algae generally grow on the
northern exposures of a roof since this exposure generally receives less sunlight. Algae are very well adapted to
extreme conditions, meaning they can survive both extreme heat and extreme cold weather conditions.
What Is The Solution? It is recommended to install Algae Resistant Shingles. These types of shingles have a specially formulated granule that inhibits algae growth, keeping your roof looking new and algae free for years.
If installing a new roof is not an option, it is recommended to clean your roof with a special roof cleaning mixture. For more information click How To Clean Roof Shingles
What You SHOULD NOT do! It is recommended by the leading roofing manufacturers to not power wash your asphalt shingle roof. Power washing shingle roofs can dislodge the granules, which can lead to premature shingle failure. The reflective shingles present in a shingled roof can both reflect the sun’s heat in the summer which will reduce cooling costs and can retain the heat in the winter thus reduce heating costs.
Where Can I get More Information? Visit North America’s largest roofing manufacturer GAF for all the information you need.

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