What Causes Dark Spots on a Roof?

Should You Worry About Dark Spots on a Roof like you see on this home's roof?

Black streaks or dark spots on your roof are more than an eyesore. They can signal shingle damage.

Here are some tips from Muth & Company Roofing to help you know how to address those dark spots on a roof.

The cause of dark spots on a roof

At first glance, those dark streaks and patches may look like dirt. The most common culprit is black or blue-green algae. The spores transfer onto a roof by the wind, and if warm, moist conditions exist, algae will begin to grow.

Shingles that contain crushed limestone, which is a great food source for algae, will also promote algae growth. Ugly spots of dark discoloration remain when the roof dries and the algae go dormant.

Algae-resistant roof shingles

If you need a roof replacement, the permanent solution to algae woes is to have Muth & Company install GAF algae-resistant shingles for you. These shingles contain copper or zinc, which are poisonous to algae.

We also recommend the installation of zinc or copper strips across the roof. The installation is every eight to 10 feet up, to help prevent future growth. The rain activates the metals and further distributes the poison over the roof!

Removing algae stains

Roofs can be dangerous, especially when wet and slippery, so let one of Muth & Company’s roofing experts in Columbus, OH, recommend an option for cleaning or a local company that specializes in roof cleaning. We avoid power washing, as this can dislodge granules off the shingles.

Keep in mind that some stains may not be able to be removed completely, so Muth & Company cannot guarantee a completely clear roof after cleaning.

If you need to schedule an inspection, cleaning, or roof replacement or just want to find out more about algae-resistant shingles, contact a professional at Muth & Company Roofing. We’d be happy to provide more information and a FREE estimate.

We’re the roofer who wants to earn your business. Call Muth & Company Roofing today at (614) 882-0900 for a FREE estimate.

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