Roofing, Siding, and Deck Blog Post

What Is That Black Stuff On My Marietta Ga Roof?

As a Marietta roofing company, we often get calls that go something to the effect of, “What is that black stuff on my roof?” The short answer is that it is most likely black or green algae growth. Almost every Atlanta roof has some sort of algae stain growing on it that is unsightly. The good news is most algae that grow on shingles isn’t a huge problem that needs to be addressed right away. Below are a few different things you can to do help prevent future algae growth and some shingle products you should consider if algae is a huge issue for your home’s appearance.

Are Black Streaks On My Atlanta Area Roof a Problem?

Generally, black algae growth on your roof is not a huge issue. There are varying disagreements about this issue, but you will find that the main industry that pushes the idea that algae growth is destructive to shingles is also the same industry trying to sell roof cleaning solutions; make of that what you will. I will note that sometimes roofs in Marietta and Atlanta can grow moss, which is destructive to shingles and can greatly reduce the expected lifetime of your roofing system. You should consider hiring a roof repair contractor to take a look at your roof if moss growth is present.

How Can I Get Black Algae Off My Roof?

There are a few different ways to clean algae off your roof, but whatever you do, don’t let anyone use a pressure washer on your asphalt shingles. High pressure can break the sealant that holds your shingles to the layer below them and remove granules that protect the fiberglass mat from ultraviolet rays. A pressure washer may temporarily enhance the beauty of your roof, but it will also decrease your roof’s life expectancy. A slightly better solution is the use of bleach and water. Spray the solution onto your roof using a pump sprayer. Then, gently wash off any residue with a water hose. You can also find roof washing chemicals at your local big box store. Follow the directions on the back of the package for best results.

What Can I Do To Prevent Black Algae On My Marietta Ga Home?

The truth is, there aren’t a ton of options for preventing algae growth on your existing roof. One option that I have seen a homeowner use is a small strip of copper attached on the ridge of their home. The copper would wash over the roof and kill any algae growth. Interestingly enough, shingle manufacturers use this same principle to help fight black algae from growing on new shingles. While you can’t do much about new black streaks appearing on your old roof, you can make sure that your Marietta Roofing contractor installs Algae Resistant shingles on your next roofing project.

If you have any questions or concerns, feel free to contact me at You can also contact Fowler Homes by filling out the form to the side, and someone will get back to you as soon as possible. If you live in the Marietta area, we will be happy to come out and take a look at your roof for you and suggest a few options for dealing with future algae or moss growth.

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