Why Roof Algae is Damaging Your Roof and How to Fix It

One of the most destructive problems for a roof (and not to mention ugly) is Gloeocapsa magma, commonly known as roof algae.

What is Roof Algae?

Pressure Brothers cleaning roof algae

Gloeocapsa magma is a cyanobacteria that contains spores of algae. It is known mostly for the black streaks and stains it creates on rooftops. The algae typically starts to grow on the North side of the roof where there is less sun exposure leading to more moisture, which allows it to continue to grow easier.

Once the bacteria continues to grow, the roof algae can and will slowly weaken the shingles of a roof by consuming the limestone in the asphalt. Not only does this process begin to make your roof look bad, it can also increase the temperature of the house because the roof will ultimately become less reflective and trap the heat, leading to higher air conditioning bills.

Shingles have also been known to begin to curl up at the corners because of roof algae. Once this happens, a cleaning is not going to be the only fix as they will eventually need to be replaced.

If not treated early, roof algae is just the beginning. Eventually, lichen forms and moss can also begin to form, which will collect seeds from bird droppings, and over a long period of time can create the growth of grass or plants between your shingles. Chances are, you prefer your flowers to grow in your lawn and not on your roof!

How To Clean Roof Algae

So, what can be done to fix this? Do the shingles need to be replaced? Do we pressure wash the roof? Do we use a large combination of chemicals to clean all the black stains off?

The best option available is a low pressure washing. At Pressure Brothers, we use a safe and highly effective proprietary mixture when providing a soft wash service. Using high pressure to wash the roof can harm the shingles and does not do a great job of removing the algae anyway. Professionals use a low pressure application to properly clean shingles on a roof.

Before and after Pressure Brothers roof algae cleaning

Once cleaned, the process of the algae beginning to grow starts all over again, so it is important to keep an eye out for more long term growth. This timeframe is always different, but can be as soon as 2 years or take up to 7 years to return. Ask your roof cleaning specialist for recommendations on what you can do to help slow down this growth process.

Many manufacturers of roof shingles include information about algae build up on the roof and typically provide information on how to maintain their shingles and provide recommendations for cleaning. Check with your shingles manufacturer for more information on their warranties.

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