The Reason You Have Those Ugly Black Streaks On Your Roof

The Reason You Have Those Ugly Black Streaks On Your Roof

The Reason You Have Those Ugly Black Streaks On Your Roof

The reason you have those ugly black streaks on your roof isn’t because of mold, mildew, or dirt. But algae. The most common is Gloeocapsa Magma, also known as blue-green algae.

This algae growth starts as tiny spots and eventually turns into visible streaks. The algae have been present on the roof for at least two months before the homeowner notices it. This alga appears black. Gloeocapsa is able to form a darkly pigmented protective outer coating that protects the algae against harmful UV rays. This is why you see those ugly black streaks on your roof. Algae can be found on any type of roofing but it is most prevalent on asphalt shingles.

Why Do Shingles Get Algae?

Algae spores can be carried by air. They can be carried by wind and animals, as well as on clothing. These spores can easily spread quickly from one rooftop to another in a neighborhood because they are airborne. This holds true for apartment buildings, condominiums, and townhomes. What is the reason roof algae seems to be more prevalent today than it was 20-years ago? Asphalt shingles were originally made of asphalt, an oil-based product, and felt material. Most shingle producers have switched to asphalt shingles, but most of them are made up of fillers like fiberglass and crushed limestone. This allows them to save money. The crushed limestone filler is the main food source for these algae.

Weather Plays A Role In Algae Growth On Shingles

Although the United States has a lot of cheaper shingles, the most favorable environments for algae growth are the southeastern United States. Because of their hot and humid summers, even areas with cold winters (like the northeast or Midwest) still have roof streaks from algae. These areas are known for their roof algae. Why is this? Why? Because the northern portion of your roof is shaded during the day when the sun shines through the sky. This shade allows moisture to accumulate, creating the perfect environment for algae growth.

Roof algae can also be caused by gutters that drain directly onto the roof or trees overhanging. Also, a damp or shaded roof will prevent the sun from quickly drying it and encourage staff to grow.

Are Roof Algae Dangerous Or Harmful?

Although roof algae aren’t dangerous or harmful by themselves, they can eventually cause the protective UV granules on roofing shingles to start to fall off. Fungus, which can also travel through the air, can combine with algae on your roof to form lichen. The shingle filler and algae are both used to feed this lichen. Lichen can grow roots, unlike algae. This makes it more difficult to remove than the algae.

How Can You Get Rid Of Black Streaks On Your Roof?

Roof algae can be easily removed by a simple roof cleaning. It is important to remember that, while a roof cleaning should not be done every so often, it could cause damage to your homeowner’s insurance policy or roof warranty. A quick internet search for how to remove black streaks from your roof will bring up many different recipes as well as commercial brands.

Most formulas include chlorine bleach (or trisodium phosphate, TSP) and water. Although lye (sodium hydroxide) is more effective than bleach, it can be corrosive so you should only use full protective gear. Oxygen bleach, also known by the brand Oxyclean, is effective and less harmful to the environment. However, it will not perform as well as formulas that contain chlorine bleach or TSP. Even chemicals that are safe for people can still cause damage to landscaping and other vegetation.

You Can Clean Your Roof Yourself

Never, ever, use a power washer to clean your roof. Even on the lowest setting. A power washer can not only cause roof warranties to be voided, but it can also damage shingles by causing the protective layer (or the shingles) to come off. It will take some preparation to clean your roof. You will need to remove lawn furniture, and you’ll need to cover the vegetation and landscape. Even if your product isn’t toxic, overspray can still cause damage to the ground. You can check the weather forecast to determine if you should clean on a cloudy or overcast day. This will reduce the chances of spraying other areas than your roof. The cleaner will not evaporate as quickly if it is cloudy or overcast.

Home improvement experts recommend this formula:

  • 1 cup trisodium phosphate (available in most hardware shops);
  • 1 Gallon bleach
  • 5 gallons water

Wear eye protection, slip-resistant shoes, protective clothing, and rubber gloves. A friend can help you with any equipment. All of the ingredients should be poured into a pump-type garden sprayer, which is often used to apply liquid fertilizers. Spray them on the roof with long, even strokes. Spraying water up at your roof can cause damage to the shingles. It is best to spray from the top and work your way down. You should clean each shingle strip to a maximum of 4 feet wide.

Let the solution sit on the roof for about 15 to 20 minutes, before you rinse it. You should not be on the roof during this time as the solution and roof algae can make the shingles slippery. After the mixture is absorbed, you can rinse it off with a regular garden house. Use slow, even strokes. You may end up with some random dirt patches if you don’t slow down and use even strokes.

Hire A Professional To Clean Your Roof

If you don’t want to climb around on a slippery roof or your shingle manufacturer will void your warranty if you try to clean your roof yourself, you should contact a professional roof cleaning service to get rid of those ugly black algae stains on your roof.

It is now a beautiful roof that has been restored without any potential damage to property, people, or pets.

Preventing Black Streaks On Your Roof

Is it possible to eliminate algae permanently? The short answer to this question is no. Roof algae are very similar to having a cold. Algae spores, like many cold viruses, are easily spread by the air. Although you can treat the symptoms, you’ll eventually develop another algae problem. This is especially true if your neighbors have it.

But don’t despair! Cleaning and maintaining your roof can prevent black streaks from returning to your roof, just like washing your hands often and eating well to avoid getting a cold. These are some tips to prevent roof algae from returning:

Keep Your Roof In Good Condition

To allow more sunlight to reach your roof, trim tree branches. This will reduce the accumulation of debris. Debris that does begin to accumulate on the roof should be cleared regularly by hand as part of a regular maintenance program. This will make it less likely that roof algae grow. You should also keep gutters and downspouts clean and free of clogs to promote proper water drainage.

A lower roof can have gutters that drain onto it, which not only encourage algae growth but also can cause water to pool on the roof, which can lead to damage to shingles and the underlying wood structure.

Install A Copper Or Zinc Strip Along The Roof’s Side

Another solution is to place copper or zinc strips underneath the row of roof shingles closest to its peak. Make sure to leave between 2 and 4 inches of this strip exposed to the elements. This means that rainwater, which will contain metal-algae-killing molecules, will wash the roof down and kill any algae.

Galvanized sheet metal, while better at killing algae than copper, is more affordable. Galvanized and copper are both available in different thicknesses. They should be available at your local home improvement shop or online. Zinc strips are made by many manufacturers specifically for roof algae removal. While zinc or copper strips can help, this won’t provide 100% protection. These strips will provide an additional layer of protection for algae spores, regardless of whether it rains or not.

New Shingles

Roof manufacturers have created copper-rich shingles to combat roof algae. It is not necessary to replace your roof’s shingles because of black spots. Roofers who suggest roof shingle replacement are not the only answer. These copper-infused shingles are a good option if your roof is in poor condition or older and you need to replace it. However, make sure you choose the longest and best warranty. These shingles have been received mixed reviews from homeowners who have used them. These shingles contain copper at different levels. Manufacturers do not regulate the amount.

To get more information on roof algae, contact us at KCG Roofing today!!

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