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What are Shingle Granules? | Roofing Boise

Shingle Granules are Part of the Process

Roof shingles are the first line of defense against the elements. They are the most important way to protect any building. Asphalt shingles are the top selling roofing material on the market today, because of their affordability and ease of use.

Manufacturing of Shingles

The manufacturing process of shingles includes granules that are embedded into the asphalt. Many of these granules are pushed down where they become a more permanent part of the shingle, but others are left on the surface. This is why some of them fall off when they are removed from the package.

Granule Deposits

After installation and over time, some of the granules can come loose. During a rain storm, they are washed off the roof and accumulate in the gutters or on the ground. A certain amount of granule loss is common and is not cause for concern.

Causes of Granule Loss

Long-term granule loss is often the result of the natural weathering process. The age of the shingle is also an indicator. Asphalt shingles deteriorate with age and begin to break down. When this happens, more and more granules are released from their base.

Mother Nature

Extreme temperature changes can affect the stability of asphalt shingles. Wind is a big culprit when it comes to damaging roofs. Hail and snow sitting for long periods on a roof create a problematic situation because it weakens the asphalt. The older the roof the more susceptible it is to damage.

Failure to Bond

The bond between the asphalt and the granules is an important one. Once the bond is broken, the roof will lose its integrity. Poor-quality shingles often wear down faster and need replaced sooner than those of a higher standard.


The granules provide a protective barrier from UV rays. As they wear off, the shingles can become brittle and break. An inspection by a professional roofer is recommended if there are any signs of undue wear or damage. They can determine the life expectancy of the current roof and alert the owner to problem areas. Fixing small issues before they become larger ones is the reason for calling a professional roofer.