What is the purpose of granules on asphalt shingles regarding UV exposure?

Granules on asphalt shingles serve a critical function in preventing degradation. These granules are made from materials such as crushed stone, which are embedded into the surface of the shingles. Their primary role is to shield the underlying asphalt from ultraviolet (UV) radiation that can lead to deterioration over time. Prolonged exposure to UV rays can weaken the asphalt, causing it to become brittle, lose flexibility, and ultimately result in failures like cracking and curling.

By providing a protective layer, the granules help to prolong the lifespan of the shingles, ensuring that they maintain their integrity and functionality throughout their intended service life. While granules may also add color and enhance the aesthetic appeal of the roof, their fundamental purpose in relation to UV exposure centers on preventing damage and degradation caused by sunlight. This protective characteristic is essential for maintaining the performance and durability of the roofing system.