---
title: Shingle Discoloration: The value of algae-resistant shingle technology
description: Algae Defender helps prevent algae growth and staining on roofing materials, keeping roofs cleaner, brighter, and protected for longer-lasting performance.
image: https://go.pabcoroofing.com/hubfs/Before-Photo_With-Black-Streaks.jpg
---

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# Shingle Discoloration: The value of algae-resistant shingle technology

![Lori Jerome - Marketing Manager](https://app.hubspot.com/settings/avatar/b4cdb9f7ac6bda9e67668d8eeb337cf3) 

[Lori Jerome - Marketing Manager](https://go.pabcoroofing.com/en-us/blog/author/lori-jerome-marketing-manager)

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![Copper Granual](https://go.pabcoroofing.com/hubfs/Before-Photo_With-Black-Streaks.jpg)

PABCO Roofing Products ' [Algae Defender](https://pabcoroofing.com/algae-defender/) shingles provide a proven, reliable option for roofs in moisture-prone regions — backed by science, field testing, and a warranty designed for real-world conditions. 

Obvious and unsightly black streaks on rooftops are a common complaint among homeowners about aging roofs, especially in wet or heavily shaded areas. These dark streaks can lower curb appeal, trigger unnecessary insurance claims, and make a perfectly healthy roof appear much older than it actually is.  

Help [homeowners](https://pabcoroofing.com/homeowners/) understand why choosing algae-resistant shingles can make a significant difference in how long their roof retains its new appearance. 

### Understanding the problem 

The dark streaks many homeowners assume are dirt or shingle failure are usually caused by cyanobacteria, also known as blue-green algae. This organism thrives in areas where moisture lingers on a roof surface, especially on north-facing slopes or in shaded areas near trees or buildings, particularly in climates with prolonged periods of wet conditions. 

The algae itself isn’t structurally harmful to the shingles. The issue is what happens after it dies. As cyanobacteria break down, they leave behind a dark, pigmented residue that clings to the shingles. Over time, this develops into the familiar black streaking pattern that gives roofs a worn or neglected appearance. Algae-resistant shingles are designed to prevent the growth of blue-green algae and the unsightly black streaks they leave behind. 

### How algae-resistant shingles work 

Most standard asphalt shingles utilize ceramic-coated granules, which provide both color and protection. Algae-resistant shingles incorporate copper-infused granules, as copper is a natural algaecide. When the roof becomes wet, small amounts of copper ions are released from the granules and wash across the roof surface. These ions make it extremely difficult for cyanobacteria to establish, helping keep the shingles clean and streak-free.  

Most asphalt manufacturers use copper granules in some form; however, the variation lies in the quantity of copper granules used and their effective distribution.  ![Ceramic coating](https://go.pabcoroofing.com/hs-fs/hubfs/Ceramic%20coating.jpg?width=1080&height=1080&name=Ceramic%20coating.jpg)

### PABCO® Roofing Products’ science-backed approach 

Because [PABCO Roofing Products](https://pabcoroofing.com/) is based in Tacoma, Washington, one of the most algae-prone regions in North America, we’ve invested heavily in understanding how algae develops and exactly how much copper is needed to resist it.  

At a long-running test facility in Granite Falls, Washington, PABCO has tested shingles built with varying copper granule concentrations. After years of exposure, our testing facility has enabled us to develop our Algae Defender technology with an optimized copper granule blend engineered to resist blue-green algae for years under harsh, wet conditions. 

### Where algae resistance matters most 

While algae can grow almost anywhere, some environments make blue-green algae far more aggressive. Contractors should strongly recommend algae-resistant shingles for roofs that experience: 

- Long periods of moisture (coastal regions, fog belts, rainy climates) 
- Slow dry-out times (cool temperatures, persistent cloud cover) 
- North-facing slopes that rarely receive sunlight 
- Tree cover or nearby structures that cast long shadows 
- Neighborhoods with heavy debris, pollen, or dust that feed on organic growth 
- Rural areas where farm activity stirs up dirt that settles on the roof 

In places like the Pacific Northwest, for example, a roof might stay wet for months at a time. Without algae-resistant shingles, black streaks are almost guaranteed.  

### Beyond appearance: The hidden risks of algae growth 

Although algae is primarily an aesthetic problem, homeowners increasingly face secondary consequences: 

- **Other growth becomes more likely:** Moss, lichen, and green algae often feed on the organic residue left behind by blue-green algae. When cyanobacteria fail to establish themselves, these organisms have a harder time gaining a foothold. 
- **Organic growth can affect roof performance over time:** While the shingle itself isn’t a nutrient source, moss and lichen can trap moisture, redirect water flow, and dislodge granules from the shingles as they root and spread. 
- **Insurance claims are becoming more common:** More homeowners are being told by adjusters that their roofs appear worn out because the black streaking mimics granule loss or shingle deterioration. In many cases, the roof is still well within its service life, it’s just stained. 

Choosing algae-resistant shingles can help homeowners avoid these unnecessary headaches and preserve the roof’s visual condition. PABCO backs this with warranty protections for Algae Defender products, offering cleaning, repair,  or replacement if cyanobacteria appear. 

### A better roofing experience 

Homeowners rely on contractors to guide them toward products that will perform in their specific environment. By educating clients about blue-green algae and the benefits of Algae Defender shingles, you help them make a choice that saves money, avoids frustration, and keeps their home looking great for years to come. 

![Lori Jerome - Marketing Manager](https://app.hubspot.com/settings/avatar/b4cdb9f7ac6bda9e67668d8eeb337cf3)

#### Lori Jerome - Marketing Manager

At PABCO Roofing Products, Lori Jerome focuses on driving brand growth through strategic planning and marketing technologies. As a brand strategist, Lori excels in marketing automation, strategic product placement, and enhancing contractor benefits programs, leveraging her expertise in marketing communications, online marketing, and social media marketing. Since 1984, PABCO Roofing Products has stood out by offering the capabilities of a national manufacturer with the personalized care of a small business. Their mission is to provide best-in-class products and build lasting relationships, driven by a team dedicated to remarkable service and support.

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