Worried about dark streaks on your asphalt roof? Learn if algae is harmful, how it affects your shingles, and the best ways to protect your Columbus home.

Are algae stains harmful to my roof?

Shingle Roofing FAQs
July 30, 2025•2 min read

Are Algae Stains Harmful to My Shingle Roof?

Short answer: Algae won’t eat away at your shingles, but it does shorten your roof’s lifespan if left untreated.

Here’s what you need to know:

What Is Roof Algae?

In Columbus and surrounding areas like Powell, Westerville, and Grove City, homeowners often notice dark streaks or patches on their shingle roofs. That’s usually Gloeocapsa magma, a type of airborne algae.

It’s most common on:

  • North-facing roof slopes (where moisture lingers)

  • Older asphalt roofs

  • Homes shaded by trees

Is It Dangerous?

Not directly—but here’s why it matters:

  • Moisture retention: Algae holds water against your shingles. Over time, this speeds up granule loss and shortens roof life.

  • Heat absorption: The dark streaks increase surface temperature, which can raise attic temps and utility bills.

  • Curb appeal: Algae stains look like damage to many buyers. It can make a solid roof seem like it needs replacement.

The Good News? You’ve Got Options.

At The Roof Champion of Columbus, we offer:

  • Algae-resistant shingles: We use shingles that contain copper or zinc granules, which stop algae from growing in the first place.

  • Safe roof cleaning: If you already have staining, we can clean it without damaging your shingles.

  • Regular inspections: Staying ahead of algae keeps your roof looking great and performing even better.

Real example: One Powell homeowner called us about replacing their roof due to black streaks. Turns out, their shingles were still in great shape. We cleaned the algae, installed zinc strips, and they saved thousands.

Want to Keep Your Roof Looking Clean?

Here’s what we recommend:

  • Trim back tree branches to reduce shade and debris.

  • Keep your gutters clear so water drains properly.

  • Schedule a pro inspection every 1–2 years.

FAQs

What causes algae on my roof?
Airborne spores land on shingles and grow in damp, shaded areas—especially on older roofs that lack algae protection.

Will insurance cover algae damage?
No. Insurance typically doesn’t cover roof algae, since it’s considered cosmetic and preventable through maintenance.

Can I pressure wash algae off?
Don’t. Pressure washing damages shingles and voids warranties. We use manufacturer-approved, soft-wash solutions to clean safely.

How long do algae-resistant shingles last?
With proper ventilation and maintenance, algae-resistant shingles can extend roof life by 5–10 years or more.

Got dark streaks on your roof? Let’s take a look—no pressure, just honest advice.
Call The Roof Champion of Columbus at (614) 639-3422 or schedule an inspection online.

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