Discoloration on Asphalt Shingle Roofs

Asphalt shingle roofs are known for being durable and visually appealing. However, over time, you may notice some slight discoloration on your roof despite always maintaining it properly. What are these stains? Can you remove them?

Discoloration on Asphalt Shingle Roofs

Read on as Mass-Tech Roofing and Building Co. discusses what these roof stains are and what you can do about them.

Algae Stains

Algae stains appear as black streaks that start from the upper slopes of your roof. Algae grow and thrive on the limestone filler used in asphalt shingle roofs and can even appear on newly constructed roofs, depending on the climate and weather conditions. They can eat away at your roofing material and can become even more of a threat if they fuse with fungi to form lichen. Fortunately, algae stains can be power washed. With highly pressurized water, you can flush out the algae from the surfaces. However, keep in mind that only algae stains can be easily removed. Lichen, on the other hand, is quite difficult to get rid of.

Rust Stains

Rust stains are common on metal roofs. They appear as red or brown discolorations bleeding out of the exposed metal parts of your roof, like the flashing or metal chimneys. These compromised metal sections must be checked for leaks and holes as they are vulnerable to leaks. Typically, these stains can be prevented with regular roof inspections and maintenance. But if the stains have become more stubborn, you can try using vinegar and scrubbing them off. Deeper and stronger stains can also be removed using oxalic acid.

Asphalt Bleed-Through

These stains appear as black streaks on your roof and are caused by the black pigment in the asphalt breaking down and bleeding off, making noticeable discolorations. They appear when your roof is nearing the end of its service life, or the roofing materials themselves are subpar. When this happens, it is best to have a pro check your roof as these stains look similar to algae stains. They are different from the black stains caused by algae since algae stains tend to follow the flow of water while asphalt bleed-through starts from the shingles themselves.

No need to keep browsing through lists of roofing companies in your area as Mass-Tech Roofing and Building Co.​ can deal with all your roofing needs! With over two decades of industry experience and service, we’re confident that we can provide solutions to your roofing issues through our first-rate workmanship and skills. For inquiries, fill out our contact form or call us at (781) 826-7663.

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