What is the primary purpose of granules in asphalt shingles?

The primary purpose of granules in asphalt shingles is to protect the underlying asphalt. These granules serve several important functions, including providing a barrier against harmful ultraviolet (UV) rays from the sun, which can degrade the asphalt over time. By absorbing and deflecting UV light, granules help to prolong the life of the shingles and prevent premature deterioration. Additionally, they can also prevent granule loss and provide a protective surface that improves the roof's overall durability against environmental elements such as rain, wind, and hail.

Granules also enhance the aesthetic appeal of shingles by offering a variety of colors and textures, which is an important factor for homeowners. This aesthetic contribution relates more to visual enhancement rather than the primary protective mechanism granules provide. Overall, the primary function remains focused on protection and durability.