Take a look around at the roofs in your neighborhood. Are there dark streaks or discolored patches on the shingles? It’s not dirt—it’s staining from airborne algae. Commonly (but incorrectly) called fungus or mold, algae is a common eyesore on roofing throughout North America. The best way to prevent this unsightly problem is by installing StreakFighter® algae-resistant shingles.
Understanding Algae Streaking
Standard roof shingles are quite susceptible to the unsightly black staining, smears, blotches, and streaks caused by algae spores. Since the roof is such a large portion of a home’s exterior, and algae is difficult and expensive to clean, the discoloration can become an aesthetic nightmare which decreases the value of a home. While studies show that algae growth is not harmful to the building envelope, the growth of algae on cool roof specialty shingles can reduce the performance of solar reflectance because the algae spreads across the face of the shingle and covers the reflecting granules that reflect thermal energy from the sun.
What Causes Black Streaks on a Roof?
Even though roof streaking is caused by what’s called blue-green algae, the streaks are black due to the dark-pigmented sheath that algae uses to protect itself from the sun’s rays.
Algae spores can quickly spread in the right conditions:
- Wind carries algae spores from roof to roof
- Hot, humid conditions promote algae growth
- Shaded areas serve as excellent breeding grounds
Algae discoloration most often occurs on east-facing surfaces but can show up anywhere on your roof. In fact, an algae infection typically takes hold well before the black streaking is visible.
How Algae-Resistant Shingles Work
CertainTeed has developed shingles with StreakFighter algae resistant technology. These shingles are made with a blend of surface granules that includes numerous copper-containing granules. Copper possesses natural anti-algae properties, and the copper in the granules is gradually released over time to provide reliable, long-term protection from algae formation to help a roof maintain its true luster.
All CertainTeed shingles are available in an Algae Resistant (AR) version that provides StreakFighter protection for a nominal cost over non-AR shingles. Download our StreakFighter brochure HERE.
StreakFighter® Algae Resistant Shingles
Our algae-resistant shingles carry a limited warranty against contamination from blue-green algae during the first 10 or 15 years (depending on the product). CertainTeed warrants that algae-resistant shingles will remain free from blue-green algae during this period and will pay, without proration, the reasonable cost to replace or clean the affected shingles.
For complete information on the StreakFighter warranty, read our ASPHALT SHINGLE WARRANTY
To explore CertainTeed’s Algae-Resistant shingle options online CLICK HERE
Products featured in this project
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Neil H.
Restoration Classic - Midnight Blue
Monogram - Wedgewood Blue
Monogram - Wedgewood Blue, Northwoods - Midnight Blue
