Algae Resistant Roofing Shingles


A Roof Algae Is Growing On Algae Resistant Roofing Shingles

Do you know what those ugly streaks are which can be seen on roofs? These dark spots (which can be found on roofs in moister and mor humid areas of the country like the Houston Texas) are algae streaks. Most homeowners notice this on their roofs and often question, what is the causes? What can be done about it? Also is this going to be an ongoing problem I will have to deal with for the life of my roofing shingles?”

These are great questions worth a good, solid answer. What you’ll find in this “Algae Resistant Roofing Shingles” post, is some informative and helpful tips and pointers to help you understand what is happening to your roof, how to prevent or resolve the issue. 

What Are Those Streaks I am Seeing On My Roof?

The roof streaks are algae staining on the roof surface. This algae is literally growing on the roof and embedding itself into your roofing shingles. This happens because of the very small spaces asphalt roof surfaces created by the coated roofing granules. In other words, with the roofing granules being irregular in shape, this provides small areas which can hold moisture allowing for a great environment for algae to grow.

As the moisture sits in these small spaces, mold and or algae begins to form in between these little areas. This typically happens on homes located in humid areas of the country, where the roofs tend to stay moist longer creating a perfect algae breeding-ground. This is most commonly seen on the north side of a home’s roof with the tendency to get less sunshine thus remaining moist for longer periods of time. 

What Kind of Algae Is Growing On My Roof?

The type of Algae that grows on roofs is called, Gloeocapsa Magma. This is a black algae which is living and is feeding on the surface of your limestone, granulated surface roofing shingles. This constant feeding will break down the shingles which will cause premature failure as it loosens the granules exposing the asphalt and fiberglass mat underneath, not a good thing to have happen.    

Algae Resistant Roofing Shingles Your Best Choice 

The most effective way (by far) to stop the roof on your home from getting those ugly roofing streaks in the first place. We recommend having an Algae resistant roofing shingles installed. These type of shingles were created for the purpose of preventing algae growth on the shingles. When installing a new roof, this is definitely the best option available to prevent your roof from getting those ugly stains which often occurs just a few years of installation. 

How Are The Algae Resistant Roofing Shingles Made? 

Have you ever noticed that when you look at a roof that has algae streaks, that there are no streaks on the downside of the metal roof projections? The reason why there are no streaks below the metal objects is because the water rolls down the roof and across the metal which is a metallic product with copper and zinc in it. This process just happens to kill the microscopic algae. As the manufacturers of the roofing shingles realized this, they actually created roofing shingles with copper and zinc which are now available for homeowners to have installed on their homes.

These shingles are marketed as AR, Algae Resistant, made with copper and zinc small granules in them for a non streaking algae resistant roof.  These roofing shingles are made with both copper or zinc granules embedded in them depending on which roofing shingle manufacturer’s shingles you choose to install.

Zinc Roofing Strps Alternative Roof Product with Zinc Strips

By doing a search on the internet you will find that there are many products on the market which will help keep the roof from getting those ugly algae streaks. One of the products is Zinc Armor. This product is a metallic strip that can be installed on the upper most point of your roof. When water rolls over it, the algae below is being neutralized (killed). This will in turn stop algae that may be trying to grow on your roofing surface.  

Algae Resistant Roof Shingles Points:

  • Algae on your roof will decreases the life of your roof
  • Algae can be cleaned off 
  • Copper and Zinc will stop Algae from growing
  • Algae resistant shingles are a great long term option
  • When replacing your roof, consider installing algae resistant shingles
  • Extra cost is nominal

Algae Resistant Roofing Manufacturers

When roofing your home located in the humid southwest of the United States, we recommend considering algae resistant roof shingles. Below is a list of algae resistant shingles manufactured by several different companies.

  1. GAF Timberline algae resistant roofing shingles. This shingle is marketed with stain guard protection to homeowners.
  2. Tamko Roofing Shingles – Algae Relief  
  3. Owens Corning – Algae Resistance  
  4. Atlas Roofing – Scotchgard Algae Resistance 
  5. Certainteed Landmark – Algae Resistance 
  6. GAF Blog – Algae 

Black Streaks on Roof - Algae StainsImpacts on the Inside The Home

There is yet another issue you may want to consider which many homeowners do not think of when it comes to roof algae. Do you think that a roof with algae growing on its surface will have any impact on those living inside the home? I can’t help but think that most definitely the answer to this question would be, absolutely!

Keep in mind that musty smell that you sense when you enter a home from the outside, could very well be a good indicator of a possible issue in the roof system. This would more be the case depending on how bad the algae problem is on the roof. Of course, the worse the algae, the greater the chances are that the roof can be contributing to the musty smell. This oder is more the case in hot and humid areas such as Houston Texas where we at Texas Home Exteriors see this issue and installs many algae resistant roofing systems. 

GAF Stainguard Algae Resistant Roofing ShinglesGAF Stainguard – Algae Resistant Permanent Roofing Solution 

Now you have a choice when it comes to replacing your roof. GAF offers a roofing system that will not streak due to the inclusion of copper and zinc built into their roofing shingles! Your new GAF roof will look great for years to come and will be backed by the GAF warranty. Now you can rest assured that you will never see those ugly algae roofing streaks again. The roof on your home will look just like new for many years to come! 

GAF Timberline HD With StainGuard Algae ResistantConclusion for Algae Resistant Roofing Shingles 

Many homeowners are not aware that their is algae is currently growing on their roof which will eventually create ugly black streaks. We recommend to homeowners to go outside and take a look around their roof for signs of this problem.

And remember, when it is time to replace your roof, we strongly recommend that you consider AR “algae resistant” roof shingles to provide you with many more years of service and the look of a new roof not to mention. you will be much less likely to encounter algae issues (not to mention breathing issues inside of your home). Check out the GAF Roofing Shingle colors and selections available. We have our famed Texas EZ Pay Financing if needed. Thank you from all of us here at, Texas Home Exteriors for visiting our site and reading this post on Algae Resistant Roofing Shingles.

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3 Responses to Algae Resistant Roofing Shingles

  1. Marla says:

    Hi there, I just seen your post on algae resistant roofing shingles. I often wondered why you could see those streaks on my roof. Thanks so much as now I understand.


    • texashomeexteriors says:


      Well thanks so much! This is why we post this information out on the web. So homeowners can have an idea and be informed as to what is going of with their roof.

  2. My brother suggested I might like this website. He was totally right. This post actually made my day as I was considering getting a new roof for my home. You can not imagine just how much time I had spent looking for this info! Thanks!

    Barry K

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