Why Your Roof Shingles Have Granules

If you have ever looked closely at your asphalt shingle roof, you may have noticed that it is covered with tiny bits of stone or ceramic that give it a textured and colorful appearance. These are granules and besides being decorative, they protect your roof from weather, sunlight, algae, and pollution. 

The Composition of Roof Shingle Granules

Roof shingle granules are minerals or natural stones. They are made from crushed rock. They have different sizes and colors and are bonded in a ceramic matrix.

Why They Are Necessary

Roof shingle granules have several functions that make them necessary for the performance and durability of your asphalt shingle roof. They protect the roof from the weather. They shield against rain, hail, snow, wind, and debris that can damage the asphalt layer underneath. They also help prevent shingles from sticking together or curling due to temperature changes.

Granules protect your home from sunlight. They reflect heat away from the roof, reducing your home's cooling load and energy consumption.

They protect the roof from algae. Roof shingle granules can be infused with copper or other metals that inhibit algae growth on your roof. Algae can cause black streaks or stains on your roof, affecting its appearance and lifespan. Some granules also have special characteristics.

Smog-Reducing Granules

These are the granules that have a photocatalytic coating that breaks down smog pollutants in the air. They are used to create green building solutions.

Highly Reflective Granules

These are the granules that have a high reflectance value, meeting the reflective codes for commercial low-slope roofs. They replace standard cap sheets for increased energy efficiency and cost savings.

The Unique Characteristics of Shingle Granules

Roof shingle granules have different sizes depending on their application and desired effect. The size of the granules affects how much they cover the asphalt layer, how much they reflect or absorb light, and how much they weigh on the roof. Generally, larger granules provide more coverage, absorption, and weight. In comparison, smaller granules provide less coverage, more reflection, and less weight.

Roof shingle granules have different colors depending on their composition and coating. The color of the granules affects how they blend with the asphalt layer, how they contrast with the surrounding environment, and how they influence the mood and style of your home. Generally, darker granules provide more contrast, more absorption, and more warmth, while lighter granules provide less contrast, more reflection, and more coolness.

Protective Coatings

Roof shingle granules have different coatings depending on their function and performance. The coating of the granules affects how they bond with the asphalt layer, resist weathering and fading, and enhance their specific features. Generally, ceramic coatings provide more durability, stability, and protection, while photocatalytic coatings provide more reactivity, functionality, and sustainability.

Roof shingle granules are an essential component of your asphalt shingle roof. Once you understand the characteristics of the granules, you'll be better able to decide on what type of roof a contractor should install on your home.

Contact a roofing contractor near you.