How Often Should You Replace Your Roof

What Are the Black Streaks on My Roof?

As a homeowner, you might witness mysterious black streaks appearing on your roof. When you find any kind of black streaks and stains on your roof, it needs urgent attention. The appearance of the outside of your home is very important.

You might wonder why your roof has black streaks? How do you remove them? Read more to get answers to those questions.

Why black streaks on the roof?

Generally, streaking and staining on roofs appears because of Algae. It is known black streaks as it comes in black stains that are caused by a particular type of algae called Gloeocapsa magma. Such growth is a type of bacteria that forms algae spores’ group together. Some specific type of algae is normally a blue or green color. This type of algae feeds on any limestone determined in your asphalt shingle roofing.

The fact is your roof might get weaker the longer algae last, growing larger and becoming noticeable makes it moister and can lead to premature aging on your shingles. It’s vital to remove algae as early as you can so your shingles don’t rot.

How to remove black streak from your roof?

How to remove black streak from your roof?

If you find any black streaks on your roof that are required to be removed, then the best way is to hire a professional that can handle the job perfectly. The major reason for cleaning your roof or repairing shingles is dangerous.

One of the major risks is falling, particularly if you don’t have safety experience or equipment. Furthermore, if you don’t have any expertise, skills or knowledge then you can end up damaging your own roof.

One should know that roof algae can be easily removed through a single roof cleaning. Occasional cleaning of the roof doesn’t harm your roof and through easy search you can get to know about different home formulas of getting rid of roof algae. Major solutions for removal of black streak involve chlorine bleach and/or trisodium phosphate (TSP) and water. While lye (commonly known as sodium hydroxide) is considered as more effective than any kind of bleach, it is corrosive and should only be applied using full protective gear.

You can also make use of Oxyclean that can be less effective but it is less environmentally damaging. It will not work with other formulas, be careful while using it.

Prevent Black streaks on Your roof

If you want to know that you can prevent black streaks on your roof? Yes, you can prevent it by performing a few steps through which you can prevent such black streaks.

Regular roof maintenance

Inspect your roof regularly so that you can clear any kind of debris that might foster algae and moss growth on your roof. Overhanging branches requires trimming on time to increase sunlight exposure to the roof surface.

You should also keep gutters and downspouts clean and free of clogs to promote proper water drainage. Do not allow gutters or downspouts from an upper roof to drain directly on a lower roof, get the extension of the downspout from the upper roof into the lower gutter.

Draining of gutters onto a lower roof not only promotes any kind of algae growth but can cause water to pool on your roof that damages shingles and underlying wood structure.

Gentle Cleaning

If black streaks are present then you consider the use of a mixture of water and mild detergent in order to clean all affected areas. You should avoid using pressure washers as it might damage your shingles.

If you are aware of the products that are used for the purpose of cleaning then only you should perform it otherwise you can check on your roof manufacturer website for details related to cleaning products. Make sure that you wear eye protection, slip resistant shoes, protective clothing and rubber gloves. It’s good if you call professional roofers to get your roof clean.

Zinc and copper strips

One of the ways to protect your roof is to install copper or zinc strips under the row of shingles closest to the peak of the roof, making sure that you leave 2 to 4 inches of the lower edge of this metal strip exposed to the weather.

Whenever you witness rain, the water that contains algae killing molecules from the metal will wash down the roof and kill any algae that might be lurking there.

On the other hand, copper works better at killing algae, galvanized sheet metal is a comparatively less expensive solution. Both copper and galvanized metal are available in diverse widths and thickness. You should remember that these copper or zinc strips will not provide 100% protection but it offers an extra layer of protection to your roof.

Professional Roof Contractor

For severe cases, you should consult a professional roofing contractor who specializes in roof cleaning and maintenance. Also, if you want to add diverse shingles to your home or strips of metal to help in preventing algae regrowth. Excel Construction Group is one of reliable and licensed roofing contractors that can assist to prevent black streak on your roof.


Roof algae can lead to black streaks on your roof that might need immediate attention. Do you take proper preventive measures to extend the life of your roof? Regular maintenance, gentle cleaning and professional help can assist you to keep your home protective from all.

Excel Construction Group professionals guide you to keep your roof well-maintained and adds to your home’s curb appeal. It’s time to safeguard your investment for the years to come.

If you have any questions about black streaks on your roof? Contact us today or visit our website to schedule free inspection from our professionals.

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