The gravel layer on a tar and gravel roof plays a vital role in protecting the roof from UV damage. It acts as a shield, preventing the underlying tar from direct sunlight exposure. Over time, this protection helps maintain the integrity of the roof, preventing the tar from breaking down due to UV radiation. This barrier ensures that the roof remains durable and resilient, even in areas with intense sun exposure. Without the gravel, the tar could degrade more quickly, reducing the roof's lifespan. By adding this layer, the roof system can last longer and maintain its effectiveness. Thus, gravel not only enhances the roof's strength but also prolongs its lifespan.