What Curling Shingles, Granule Loss, and Roof Stains Really Mean for Your Roof

Have you noticed your shingles curling up, bare patches forming on your roof, or dark streaks running down the surface, or black streaks running down one side? Have you wondered if these are just signs of aging or early warnings that your roof is starting to fail?

At Hoel Roofing, we’ve inspected hundreds of roofs across Indiana. One of the most common frustrations we hear is that homeowners don’t know whether these roof issues are cosmetic or a sign of real trouble. Indiana’s weather makes these problems worse. Between humid summers, heavy rainfall, and freeze–thaw winters, Indiana roofs face extra stress. Curling shingles and granule loss often appear sooner here than in drier climates, especially on south-facing roof slopes that take the brunt of the sun.

In this article, we will discuss what each issue means, what causes it, and when it’s time to take action.

What Causes Shingle Curling? Is It Always a Serious Problem?

Curling shingles are one of the most common warning signs homeowners notice. It means the edges of your shingles are lifting upward or the corners are bending.

What Causes Shingle Curling?

• Age: As asphalt shingles get older, they dry out and lose flexibility.
• Poor attic ventilation: Heat trapped in your attic cooks the shingles from underneath.
• Improper installation: Shingles nailed too high or with too few fasteners can lift over time.
• Manufacturer defects: Sometimes, it’s not the roofer, it’s a faulty batch of shingles.

Can Curled Shingles Be Repaired or Do They Need Replacing?

It depends on how widespread the problem is.

• If less than 20% of shingles are curled, a repair or partial replacement might be enough.
• But if most of the roof is curling, it’s likely near the end of its lifespan.

Pro tip: Schedule an inspection if you notice multiple curled spots. A roofer can confirm whether it’s surface-level wear or a deeper ventilation issue.

Is Granule Loss A Sign of Normal Aging or Roof Damage?

Granules are the tiny sand-like pieces that coat asphalt shingles. They protect your roof from UV rays and weathering. There’s a big difference for your health of your roof and your wallet between normal granule loss and excessive granule loss.

• Normal: Finding a few granules in gutters after heavy rain or a new roof installation is expected.
• Warning sign: Bald patches, uneven coloring, or shiny fiberglass beneath indicate the protective layer is gone.

Without granules, your shingles lose their ability to reflect sunlight. Granule loss accelerates cracking and shortens their lifespan, sometimes by several years. If your roof is still under warranty, early granule loss may qualify as a manufacturer’s defect.

What Do Roof Stains and Discoloration Mean?

Dark streaks or stains on your roof can look bad, but they are not always dangerous. Most black streaks are caused by algae, not mold. Algae feed on the limestone in shingles, especially in humid or shaded areas. It’s mostly cosmetic, but it can accelerate your roof’s aging if left untreated.

If stains are paired with soft spots, sagging, or ceiling water marks, that’s a red flag. It could mean trapped moisture, decaying wood, or hidden leaks beneath the shingles.

To prevent roof stains:

• Install zinc or copper strips near the ridge; rainwater carries metal ions that stop algae growth.
• Schedule regular cleanings with a professional (avoid pressure washing).
• Make sure your attic has proper ventilation to reduce moisture buildup.

How to Know If These Roof Problems Mean It’s Time to Replace Your Roof

Here’s a quick guide to help you decide:

The best bet is to get a no-obligation roof health inspection before assuming replacement. A good roofer will tell you exactly where your roof stands, and what can wait.

How to Prevent Curling Shingles, Granule Loss, and Roof Stains

You don’t have to be a roofing pro to keep your roof in good shape. A few simple habits can make a big difference:

• Keep your attic cool and ventilated: When heat builds up inside your attic, it “bakes” shingles from underneath, causing them to curl or lose their protective granules. Good airflow helps them last longer.
• Clean your gutters a few times a year: Clogged gutters trap rainwater, which can sneak under shingles and lead to stains or soft spots on your roof and fascia.
• Trim trees and clear off debris: Branches that hang over your roof drop leaves and hold moisture, which feeds algae streaks (a common problem in Indiana’s humid summers).
• Schedule a roof inspection every year: A professional can spot early signs of wear, like loose shingles or flashing issues, before they turn into leaks or costly repairs.
• Consider algae-resistant shingles or metal strips: Adding copper or zinc strips near the roof ridge can help prevent dark streaks that often appear after rainy or humid seasons.

Frequently Asked Questions (FAQ) On Shingle Curling, Granule Loss, & Roof Stains

1. How long should asphalt shingles last?
   Most asphalt roofs last 20–30 years, depending on quality, climate, and maintenance.
2. Can curled shingles be glued down?
   Some DIY guides suggest this, but it’s not recommended since curled shingles often have lost their flexibility or seal. Replacement of the affected area is safer.
3. How can I prevent granule loss?
   Keep gutters clear, ensure attic ventilation, and schedule regular roof inspections to catch small issues before they worsen.
4. What’s the best way to remove roof algae or black streaks?
   Use a low-pressure wash or a bleach-based roof cleaner. Avoid power washing — it can strip granules off your shingles.
5. How do I know if my roof warranty covers damage?
   Manufacturer warranties cover material defects (like premature granule loss), while contractor warranties cover installation errors. Review your paperwork or ask your roofer to confirm coverage.
6. How often should I have my roof inspected?
   Ideally, once a year, or after major storms. Regular inspections help catch curling, leaks, or granule loss before they become major repairs.

When Should You Call A Professional For A Roof Inspection?

Not every curling shingle or dark streak means you need a new roof — but it does mean it’s time to take a closer look. You should schedule a roof inspection if:

• You’ve experienced a recent hailstorm or strong winds in your area.
• Your roof is 10 years or older and hasn’t been inspected in the past year.
• You see interior water spots or ceiling stains after rain or snow.
• You’re selling or buying a home and need a clear assessment of the roof’s condition.

Your roof’s age, slope, shingle type, and location in Indiana’s unpredictable climate all play a role. If you can’t decide whether right now might be the right time to get a roof repair, check out our guide on Should I Fix My Roof Now or Wait? Risks, Costs, and Insurance Rules Explained. 

Think your roof may be showing warning signs? Book a free roof inspection today with Hoel Roofing. We’ll take a look, document everything, explain the difference between cosmetic and serious issues, and help you make the smartest next step for your Indiana home.

We’ll inspect it, document it, and tell you the truth, no pressure, no games. Contact us to schedule your free roof inspection.