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How To Tell If Your Roof Stains Are From Black Algae

Gable Dormers on Residential HomeMany roofs can suffer from black or dark roof stains, but how do you tell if they are from black algae and not something else? Not all roof stains are caused by black algae. There are a number of things that can cause black roof stains.

Pitched roofs have a protective layer below the shingles called felt underlayment. As a roof ages, the materials can bleed or disintegrate. This can result in very similar roof stains as black algae. But the stains can also result from extractive bleeding of asphalt, organic debris, soot, or dirt.

Depending on the color of the stains, you can rule out some other causes. For instance, other forms of algae are generally green, yellow or brown, and rust from flashing or iron in the water and soil is red. Many shingles are made of limestone which has calcium carbonate in it that supports algae growth. The experts at your Fairfield County Roof Cleaning company can help you determine the cause of dark roof stains.

Identifying Black Algae Roof Stains

If the stains are dark black or brown, it could be black algae. Here are some ways to tell black algae roof stains apart from other dark roof stains.

Examine the stains and look for a correlation between overhanging trees or chimney areas. If the black stains are near these areas only, it’s likely they are not from black algae, but conversely black algae loves shaded areas. A sooty chimney or tree debris accumulation could be the cause of the unsightly stains.

The best way to tell black algae stains apart from other stain causes is to examine a sample under a microscope. But we don’t all have the luxury of doing this. A sample can be taken by applying a piece of clear packing tape and taking it to a laboratory to examine under the microscope.

But other than this more definitive method of identifying black algae growth is to examine whether the stains on the roof surface are in a uniform pattern covering a wider area. If this pattern occurs in shaded areas, it likely is black algae growth.

Extractive bleeding of roofing felt underlayment will generally occur all over the roof with more streaks rather than a uniform pattern. So the question is, what type of pattern are the black stains making?

Solutions For Black Algae Roof Stains

There is no permanent way to avoid black algae growth on your roof as the spores are everywhere, but you can control the substance. A chemical solution can be used to eliminate existing algae growth and there are roof coatings and sealers available to keep it away for some time.

The growth of black algae, other species of algae, mold, fungi, and mildew will also be treated and prevented with these solutions.

Sherwood Roof Cleaning & Power Washing is the local Fairfield, CT experts at treating black algae roof stains. If you have questions about black algae roof stains or need help with any other roof cleaning problem, just give us a call.

More Tips on Roof Cleaning

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