moss on roof

An Easy Way to Rid Your Home of Roof Stains

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Your roof is the crown of your home and completes its “curb appeal.” And while your roof may be fully intact and not in need of replacement, it may still be detracting from the overall look of your home due to streaks and staining.

What Causes Roof Stains?

While there are a few potential culprits, the most common is Gloeocapsa magma, a type of algae that spreads through the air and can colonize on roofs. Once it takes hold, it will proliferate, particularly on the north side of the home, causing dark streaking and staining on roofs. While this specific type of algae is normally a blue or green color, it can develop a hard outer shell that will darken to protect the organism from the sun. Depending on the roofing materials, it can appear very dark and even black, and show up in long streaks down the roof. Not exactly the look you were going for with your home. 

While Gloeocapsa magma can occur in many parts of the country, it’s more common in hot, humid places and grows year-round in the south. Seasonally, it can plague many other parts of the country, including Connecticut. 

Will the Stains Deteriorate My Roof?

The growth can cause roof materials to deteriorate more quickly than they would normally, putting you on the hook for replacing your roof more often. Essentially, the algae begin to “feed” on the limestone in asphalt roof shingles. Left there, it will worsen and become darker and more noticeable, trapping water against the shingles, which will speed their decay. 

One of the ways to prevent this from happening is to replace the roof with algae-resistant shingles. But this is an expensive option that may not be necessary if the roof has no structural problems.  

Zinc Strip Installation

At Brouder Roofing, many customers ask what they can do about roof staining and algae/moss growth. One very effective approach that lasts between five to eight years is the installation of zinc strips.  It’s a relatively inexpensive way to kill the growth that’s there and prohibit new growth without using chemicals that can damage shingles and the environment. 

Why do zinc strips work? When rainwater comes in contact with the strips, it naturally produces a solution of zinc carbonate, a known fungistat, or substance that inhibits plant growth. This zinc carbonate-rich water flows down the roof, preventing algae, moss, and fungus from growing. The moss that’s already there will eventually wither, die, and slough off, gradually eliminating stains. (Of course, you can speed the process by having the roof cleaned before the installation of the zinc strips.)

Consult a Professional

Brodeur Roofing is proud to be a GAF-certified roofing contractor serving Connecticut. We offer a 50 Year Weather Stopper Plus Warranty with every GAF roofing system. By teaming up with GAF, we are able to provide our customers with an array of high-quality roofing products that will withstand the elements and look great on their homes. For more information or a free quote, call 860-838-1279 or visit our website

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