What Causes Black Streaks on Roof Shingles?

Published: September 29, 2023 by Steven Griffin

Need help removing black streaks on your roof? Call Sugar Land Roofing, LLC at 832.944.7663 today!

Black streaks on a roof, while distasteful, are common. Sometimes homeowners mistake them for water stains after heavy rainfall, but if they remain during a hot Sugar Land, TX, day, they signal another concern. To find out what causes black streaks on roof shingles and remedy it immediately, contact Sugar Land Roofing, LLC, your professional roofing company in Greater Fort Bend County.

What Are the Black Streaks on My Rooftop?

Algae formations on rooftops create black streaks, especially on shingles. The rooftop fungus, Gloecapsa Magma, is usually blue-green but darkens according to the environment. If you receive plenty of sunlight, especially from the south, the algae grow a protective black outer layer that keeps out the sun’s rays. 

Unfortunately, algae are unnoticeable as they form. They become apparent when they darken, within a few weeks to a few months. What’s more, while they don’t pose an immediate threat to your home, these unsightly splotches continue to spread over your roof’s surface unless you take action by calling well-trained roofing contractors in Missouri City, TX.

What Causes the Black Streaks?

Algae growth originates from moisture and nutrients, which causes black streaks on roof shingles. Asphalt shingles consist of crushed limestone that provides calcium carbonate for the algae. When rain hits the limestone, the mix creates a healthy habitat for algae reproduction.

Algae also love high humidity, so long as it isn’t in direct sunlight. Down south, we suffer excessive rooftop discoloration compared to states further up north, especially on shaded rooftops on our 90-degree summer days. The shade from larger structures or trees prevents fast evaporation in damp areas and promotes constant dripping onto your rooftop.

However, your rooftop doesn’t have to be the origin point of algae. The porous fungus releases spores that attach to clothes, animals, and people, transferring to other rooftops. They travel between houses via the wind, settling onto a new roof to reproduce. 

How Do You Get Rid of the Dark Streaks?

Now that you know what causes black streaks on roof shingles, you’ll want to clean the dark streaks yourself. However, even the occasional cleaning without professional assistance may harm your asphalt. Some Texan residents use a pressure washer, which damages and dislodges shingles, or toxic cleaners without protective gear.

Sugar Land Roofing, LLC, delivers quality care during the cleaning process. We use abrasive cleaning solutions like chlorine bleach, oxygen bleach, or trisodium phosphate, depending on your preference. We then gently wash away the cleanser to promote roof material longevity.

The Contractors for Your Sugar Land Home

Simply ignoring what causes black streaks on roof shingles and how to prevent them leads to weakened asphalt and a vulnerable roof structure. Also, cleaning the roof once doesn’t keep it safe from future spores. 

Schedule regular algae cleanings with the exceptional Sugar Land Roofing, LLC, in Sugar Land, Missouri City, and surrounding areas. Call 832.944.7663 for more on angled and flat roofing pros and cons, including the best environment for algae growth and how to eradicate the issue today!

About Steven Griffin

Steven Griffin has been in the roofing industry for over 30 years. He has worked with a host of roofing companies throughout Florida and Texas. He started Sugar Land Roofing with a vision of bringing quality roofing services at an affordable price to those living in the Greater Houston, Texas area.