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What Are Granules on Shingles and Why Are They Important?

Aug 25, 2025 | Roofing Services

Architectural Shingles

What Are Granules on Shingles and Why Are They Important?

When you look at the roof of your home in Southeast Michigan, you may notice that your asphalt shingles aren’t smooth. They have a gritty, sandpaper-like texture. That grit is made up of tiny pieces of crushed stone, ceramic, and minerals, called shingle granules. While they might seem like a small detail, granules play a huge role in protecting your roof, your home, and your investment.

In this blog, we’ll break down what shingle granules are, why they matter, the problems that come with granule loss, and what Southeast Michigan homeowners can do to protect their roofs.

What Are Granules on Shingles?

Granules are the outer protective layer of asphalt shingles. They are made from crushed rock coated with ceramic or mineral coloring. Manufacturers embed these granules into the asphalt surface during the shingle production process.

Granules serve several purposes:

  • Protection – They shield the asphalt layer underneath from UV radiation and weathering.

  • Durability – They add strength and weight to shingles, helping them resist wind and hail.

  • Aesthetics – Granules give shingles their color and style options.

  • Fire Resistance – Some granules are specially designed to improve fire resistance.

Without granules, shingles would quickly break down under the harsh Michigan sun, heavy rains, ice, and snow.

Why Granules Are So Important for Michigan Roofs

In Southeast Michigan, we deal with four very different seasons—hot summers, freezing winters, wet springs, and windy falls. Shingle granules are especially important in this climate because they protect against:

1. UV Rays and Sun Damage

Even though Michigan isn’t the sunniest state, UV rays still break down asphalt shingles. Granules act like sunscreen for your roof, preventing the asphalt from drying out, cracking, and curling.

2. Heavy Rain and Moisture

Without granules, water could seep directly into the asphalt base of the shingle. Granules create a textured surface that helps shed water, preventing leaks and premature deterioration.

3. Ice and Snow

Southeast Michigan winters bring heavy snow, ice dams, and freeze-thaw cycles. Granules provide traction for melting snow and ice while protecting shingles from damage caused by expansion and contraction.

4. Wind and Hail

Storms off the Great Lakes can bring high winds and hail. Granules add a protective layer that absorbs some of the impact and helps keep shingles intact.

What Happens When Granules Are Lost?

Granule loss is one of the first visible signs that your roof may be aging or damaged. If you’ve ever seen small, sand-like particles in your gutters or at the bottom of your downspouts, those are shingle granules washing away.

Here’s why granule loss matters:

  • Reduced Lifespan – Shingles without granules degrade much faster.

  • UV Exposure – The asphalt base gets exposed, leading to cracking and curling.

  • Leaks – As shingles wear down, water can penetrate your roof system.

  • Energy Efficiency – Granules help reflect sunlight. Without them, your home may absorb more heat, increasing cooling costs in the summer.

  • Curb Appeal – Bald spots on shingles make a roof look worn and unattractive.

Common Causes of Granule Loss

Not all granule loss means your roof is failing. Some shedding is normal, especially right after a new roof installation. But consistent or heavy loss can signal a bigger problem.

1. Age of the Roof

Most asphalt shingle roofs in Southeast Michigan last 15–25 years, many times this is shorter than the warranty period because the roof was not installed with proper ventilation. As shingles age, granules naturally loosen and wash away.

2. Severe Weather

Hail, high winds, and heavy rains can knock granules loose. In our region, summer thunderstorms and winter ice are major culprits.

3. Poor Ventilation

If your attic isn’t properly ventilated, shingles can overheat from below, weakening the asphalt and loosening granules.

4. Foot Traffic on the Roof

Walking on shingles scrapes off protective granules. It’s always best to limit foot traffic on your roof whenever possible.

5. Manufacturing Defects

Though less common, poor manufacturing or defective shingles can cause early granule loss.

How to Spot Granule Loss on Your Roof

You don’t need to climb up on your roof to tell if you’re losing granules. Here are a few easy signs to watch for around your Southeast Michigan home:

  • Granules in Gutters or Driveway – Check your gutters and the ground after storms.

  • Bald Spots on Shingles – Look from the ground for shiny or bare asphalt patches.

  • Color Changes – Shingles that appear blotchy may have lost granules.

  • Curling or Cracked Shingles – Often accompanies granule loss.

If you’re unsure, a professional roofing contractor in Metro Detroit can perform a safe inspection.

Why Granules Help with Energy Efficiency

Energy bills in Southeast Michigan can skyrocket in both summer and winter. Shingle granules play a role in energy efficiency:

  • Reflective Granules – Some modern shingles include specially coated granules that reflect more sunlight, helping keep your attic cooler.

  • Insulation Protection – By preventing water infiltration, granules help protect attic insulation from moisture damage.

  • Temperature Control – Shingles without granules absorb more heat, making your HVAC system work harder.

Choosing shingles with high-quality granules can save money on energy costs in the long run.

Maintenance Tips to Protect Shingle Granules

While granule loss is inevitable over time, homeowners can take steps to slow it down and extend roof life.

1. Keep Gutters Clean

Clogged gutters allow water to back up, which can loosen granules and damage shingles.

2. Trim Overhanging Trees

Branches rubbing on your roof can scrape off granules and damage shingles.

3. Improve Ventilation

Proper attic ventilation keeps shingles from overheating, helping them last longer.

4. Schedule Regular Roof Inspections

Have a Southeast Michigan roofing professional inspect your roof every 1–2 years, especially after storms.

5. Avoid Pressure Washing

Power washing strips granules right off shingles. Instead, use gentle cleaning methods for moss or algae removal.

Repair vs. Replacement: What to Do About Granule Loss

If you notice granule loss, the next step is figuring out whether your roof needs repair or full replacement.

  • Minor Granule Loss – A small amount is normal and usually nothing to worry about.

  • Localized Damage – If only a few shingles are affected (from wind or branches), repairs may be possible.

  • Widespread Granule Loss – If large areas are bald or your roof is 15+ years old, replacement is usually the best option.

A professional roofer in Southeast Michigan can give you an honest assessment. Sometimes replacing a roof before major leaks occur saves money and prevents interior damage.

Choosing the Right Shingles for Southeast Michigan

When replacing your roof, it’s smart to choose shingles designed for durability in our local climate. Look for:

  • High-Quality Granules – Ensure shingles use durable, ceramic-coated granules.

  • Impact-Resistant Options – Class 3 or Class 4 shingles are better against hail and storm damage.

  • Algae-Resistant Shingles – Southeast Michigan’s humidity can cause algae staining, but some shingles come with copper-infused granules that prevent it.

  • Energy-Efficient Granules – Reflective granules can help lower cooling costs in the summer.

Why Work with a Local Roofing Contractor

Granules may seem small, but they make a huge difference in how well your roof performs. When you’re worried about granule loss or considering a roof replacement, it’s important to work with a local Southeast Michigan roofing contractor.

Local roofers understand:

  • Michigan Weather Patterns – From lake-effect snow to spring storms.

  • Local Building Codes – Ensuring your roof meets regulations.

  • Shingle Brands That Work Best Here – Not all products hold up equally in our climate.

Final Thoughts

Shingle granules might be tiny, but they are one of the most important parts of your roof. They protect against UV rays, storms, snow, and moisture—all of which Southeast Michigan homeowners face year after year.

If you’ve noticed granules in your gutters, bald patches on your roof, or signs of wear, don’t ignore it. A roofing inspection can help you catch problems early and avoid expensive damage.

At Level Up Improvement, we specialize in roofing, siding, and exterior home improvements throughout Metro Detroit and Southeast Michigan. Whether you need a roof inspection, minor repairs, or a full replacement, our team has the expertise to protect your home.