What is the primary purpose of granules on asphalt roofs?

The primary purpose of granules on asphalt roofs is to provide UV protection. These granules are made from materials that reflect sunlight, helping to prevent the asphalt underneath from deteriorating due to ultraviolet radiation. By deflecting UV rays, granules help extend the lifespan of the roofing material, reducing the risk of damage that can occur from sun exposure, such as blistering and cracking.

While the granules do contribute to the overall aesthetic of the roof and are involved in some degree of waterproofing by providing a protective top layer, their key function is primarily in safeguarding the underlying materials from harmful effects of UV radiation. This plays a crucial role in maintaining the roof's integrity over time, ensuring that it continues to perform its function effectively.