Bealing Roofing & Exteriors in Hanover, PA

What Should You Do About Stains on Your Roof/Shingles? in Hanover, PA

Roof stains taking away from the overall beauty of your home?  Wondering what is causing those dark streaks on your shingles? The culprit is algae, and it is common in the Eastern United States. There are other causes of roof stains as well, including rust stains from chimneys, vegetation stains if you have trees around the home, and salt stains from rainwater. Let’s take a look at what you should do about stains on your roof.

Algae Stains

To clean algae stains off a roof, you need oxygen bleach. Mix the bleach with an equal part of water and spray wash the roof. Do not use a pressure hose to do this! The intense pressure from a pressure washer can damage your shingles. If this does not work, or the results are not as good as you hoped, call a professional. They will use a stronger cleaner made up of a trisodium phosphate solution. Trisodium phosphate is toxic and requires special protective gear when working with it! 

Rust Stains

Rust stains are common around older metal chimneys. As the chimney ages, rust stains will streak down your roof. Newer, stainless steel chimneys help prevent this. To clean rust stains, use oxalic acid, which will also prevent future rust.

Vegetation Stains

Vegetation stains are common if you live near trees. These can occur from seeds, berries, leaves, and other debris that may fall from trees onto your roof. These can be cleaned using the same method noted above for algae. 


The main culprit for stains in our area will be algae. One way to prevent algae from forming is to insert strips of zinc or copper under your shingles closest to the roof peak. Leave about 1-2” exposed. When it rains, the rainwater will wash metallic atoms off these strips down to the roof below. Metallic atoms have a superpower. They kill algae that are trying to form on your shingles! 

Algae will thrive in damp, shaded areas. Trim back nearby trees so your roof will receive the maximum amount of sunlight. This will keep your roof dry and keep algae at bay. Bottom line, with some elbow grease and determination, you can prevent future stains. 

Following these tips will help you prevent those unsightly streaks from forming on your roof and help you get rid of the ones you already have! If you have questions about tough stains, call a local roofing company you can trust.  Bealing Roofing & Exteriors, LLC has the experience and know-how to not only install roofs but to make sure that roof looks beautiful for years to come.

Give us a call!

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