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How To Remove Mold, Mildew, and Algae From Your Roof

Mold, mildew, and algae are significant problems for any home, but can be even more persistent in warm and humid climates such as the South or the Midwest. As the snow starts to melt and the temperatures rise, you may start to notice dark streaks and stains on your asphalt shingles. While not dangerous, this common occurrence can lead to more serious consequences down the road if not handled properly. Fortunately, there is a wide range of ways to handle mold, mildew, and algae that can keep your home looking fresh. Learn all about how to remove contaminants and protect your home from moisture with the roofing experts at Shanco today!

Why are there dark streaks and stains on my roof?

Dark streaks and stains are a surprisingly common occurrence in the spring and summer. Residual moisture leftover from melting snow and humid air help to create a perfect breeding ground for microbes in and under your shingles. While often mistaken for mold and mildew, the cause of streaks and stains is typically a blue-green alga known as Gloeocapsa Magma. Capable of being transmitted in a wide range of ways, from wind and water to birds and other animals, it works its way into and underneath asphalt shingles before spreading. Most often found on northern-facing roofs, it thrives in shady and damp areas.


What should I do about dark streaks and stains on my roof?

You may be asking yourself what to do with mold, mildew, and algae on your roof. Though you may be able to handle it, our roofing professionals don’t suggest it. At Shanco, we’ve seen how dangerous going out on rooftops can be, and we would strongly advise against going out there without proper equipment and assistance. Let us handle it for you! We can safely and quickly remove any stains or streaks so you don’t have to worry about it. 


How to remove mold, mildew, and algae

Again, while we don’t encourage it, you can handle mold, mildew, and algae yourself. The biggest thing to keep in mind is to completely remove the stains and streaks, otherwise, they will just come back. If you have an asphalt shingle roof with mold, mildew or algae, there are several ways to effectively remove it. 


By far the most effective method of removing dark streaks and stains is with a product designed to do just that. The most common are Wet and Forget, and Spray and Forget, and can be found in hardware stores across the country. Simply attach directly to your home’s hose, spray, and let it sit. Easy!


If you don’t want to buy a product, you can also create a cleaning solution by mixing 1 part oxygen bleach cleaner with 1 part water. This can be sprayed or poured over the affected area of your roof, killing the algae. Let the solution sit for 30 minutes before cleaning with a hose. If you choose to use this method, please be careful. Algae, mold, and mildew can make your roof extremely slippery when wet. Better yet, spray your roof from a ladder or call the professionals! 


Last but not least: Do not pressure wash your roof. This can cause lasting damage to your shingles, reduce the lifespan of your roof, and cost you hundreds of dollars in repairs. 

Shanco knows roof repair

If you’re struggling to deal with recurring mold, mildew, algae, and moisture problems, it may be time to consider a roof repair or replacement. Fortunately, the experts at Shanco can help! We offer free roof inspections to determine the cause of your moisture problems, and work with you to fix them. We have been providing professional roofing repair and replacement services to Maryland, Washington, DC, and Virginia for over 20 years, and can renovate your roof to handle anything mother nature may throw at it. Contact us today to learn more!

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