10/06/2025
🌿 Algae on Roof Shingles, What You Need to Know:
As roofing professionals, we often get calls from homeowners noticing dark streaks or greenish stains on their roofs. That’s usually algae growth a common issue in Alberta and across Canada, especially in areas with humidity, shade, or poor ventilation.
🔍 Why It Happens
Algae, typically Gloeocapsa magma, thrives in moist environments and feeds on the limestone filler found in many asphalt shingles. Over time, this can spread across the roof, making it look old and neglected even if it’s still in good condition underneath.
⚠️ Why It’s a Problem
While algae doesn’t immediately damage shingles, it can lead to several long-term issues if left untreated:
premature aging: Algae retains moisture, which can cause shingles to deteriorate faster.
Reduced energy efficiency: Dark streaks absorb more heat, raising attic temperatures and increasing energy costs.
Curb appeal loss: A roof covered in stains lowers the visual value of your property and may affect resale potential.
Mold and moss growth: Algae buildup often attracts moss, which can lift shingles and lead to leaks.
đź§ą Maintenance & Prevention Tips
Here are a few expert recommendations from our team at Galindos Roofing to keep your roof clean and protected:
1. Regular Inspections: Have your roof inspected at least once a year, ideally in spring or fall. Early detection makes all the difference.
2. Gentle Cleaning: Avoid pressure washing! It can strip away protective granules. Instead, use a soft wash solution designed for roofs.
3. Zinc or Copper Strips: Installing these near the ridge line helps prevent algae growth naturally when rainwater runs down the roof.
4. Trim Overhanging Branches: Let sunlight and airflow reach your roof algae thrives in shade and moisture.
5. Upgrade to Algae-Resistant Shingles: Many modern shingles, including premium lines from Malarkey, BP, and IKO, have built-in algae resistance for long-lasting protection.
đź’ˇ Final Thought
Taking proactive care of your roof not only keeps it looking new but also extends its lifespan and maintains your home’s overall value.