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Choosing the Right Roof for Your Home: Pt. III – Algae Resistance


Algae on the roof? The black spots and streaks on your roof are unsightly and are hurting your property values! But there is no need to fear! Research into algae growth as well as recent roofing innovations can help rid your roof of these ugly marks.

How to Prevent Algae on the Roof

If you live in a coastal or humid region, roof algae may be a concern to you. Often mistaken as mildew or mold due to its dark coloring, algae accumulates on roofs all across the United States, especially in damp and humid areas. The black streaks you see on many roofs is the most common form of algae in North America, blue-green algae. This type of algae protects itself from the sun by producing a dark covering, giving it is recognizable black hue on the rooftops of many homes and buildings. Although algae on the roof is an eyesore, there is no scientific evidence that it is harmful to your roof. But this does not mean that your home is completely uninfluenced by algae, as the presence of algae can significantly harm your property value.

Regular Cleaning

The most common way of preventing algae growth on your roof is regular cleaning. This is easily done by applying a 50/50 mixture of chlorine bleach and water to the algae-covered areas, and then allowing the mixture to sit for 15 minutes before thoroughly spraying off the areas with water. Over time, the algae will begin to fade or loosen, however regular maintenance will be required to prevent future growth. You can also help discourage algae growth by clearing any fallen debris from your roof and by keeping your gutters clean to ensure proper water drainage.

New Algae-Resistant Roofing Materials

If regular roof cleanings don’t fit into your schedule, innovations in roofing technology have provided us with new roofing materials that can resist algae growth. These materials are offered by most roofing manufacturers, and prevent algae growth by infusing shingles with bits of copper, a material that is not conducive for algae growth on the roof. Algae-resistant shingles can commonly be identified by “AR” in their description, and most often come with a warranty. However, make sure to carefully read through the warranty, as all manufacturer warranties are not the same.

If algae growth is pestering your roof, algae-resistant shingles may be the answer. Make sure you take your time to do your own research and contact a trusted contractor. Doing a little homework and speaking with an experienced tradesman can go a long way in helping you make a confident decision for your home.