Aug 14, 2024
5 min read
Algae
Definition:
Microscopic plant organisms that can grow on roof surfaces, particularly in humid climates, causing dark streaks or discoloration on shingles and other roofing materials
Have you noticed dark streaks or blotches on your roof that make the shingles look dirty or old? Those marks are often caused by algae growth, not dirt or mold. In North Texas' warm, humid climate, microscopic algae called Gloeocapsa magma land on your roof and begin to grow.
As they mature, they produce pigments that turn shingles brown or black. While algae does not typically compromise the structural performance of your shingles, it does harm the look of your home and can affect resale value. Manufacturers warn that excessive algae growth may even void some roof warranties. Understanding what causes algae and how to prevent it will help you keep your home looking its best.
What causes the dark streaks and algae on North Texas roofs?
The primary species responsible for roof streaks is Gloeocapsa magma algae, a cyanobacteria transported through the air by wind. It thrives in the warm, humid weather common in Dallas–Fort Worth. These spores collect on shingles, especially on north-facing slopes that stay damp and shaded. Homes near large trees, ponds, or open fields often see faster growth because of the increased moisture and shaded environments.
When does roof algae typically appear and how can it be prevented?
Homeowners often notice discoloration three to five years after a new roof installation. To prevent growth, there are two common approaches:
Routine Maintenance: Cleaning the roof with a manufacturer-approved diluted chlorine bleach solution.
Structural Prevention: Installing copper or zinc strips near the ridge, or choosing algae-resistant shingles during a reroofing project. For long-term performance, professionals recommend combining these materials with proper attic ventilation to ensure the roof dries quickly.
What are the professional solutions for treating and resisting roof algae?
From a professional standpoint, manufacturers like Owens Corning offer shingles with proprietary technologies, such as StreakGuard® protection. These products incorporate copper-lined mineral granules that slowly release copper ions to inhibit algae growth for many years. When cleaning an existing roof, professional roofing contractors follow strict guidelines: mixing a 1:1 bleach-to-water solution, spraying gently, and rinsing thoroughly. High-pressure washing should always be avoided as it dislodges protective granules and shortens the roof's life.
Why is a professional roof inspection necessary for algae issues?
A trustworthy roofer will inspect the roof to identify whether the discoloration is due to algae, moss, or lichen, as each requires different treatments. At Arrington Roofing, we treat your home as a system. We use premium algae-resistant materials and safe cleaning methods to restore your roof's appearance and protect your investment. Book a free roof and envelope inspection today to ensure your North Texas home stays beautiful and your roof warranty remains intact.
