Over time, which characteristic changes in roofing materials as they age?

As roofing materials age, one of the most significant characteristics that changes is their reflectivity and emissivity. Reflectivity refers to the ability of a surface to reflect sunlight, while emissivity is the ability of a surface to emit thermal radiation. Over time, exposure to environmental factors such as UV radiation, moisture, and pollution can degrade the surface of roofing materials. This degradation often leads to a decrease in reflectivity, meaning the roof can absorb more heat, which can raise cooling costs in warmer climates.

As materials weather, they may also lose their original color or become discolored, which can further impact their reflectivity. Proper maintenance and periodic inspections can help mitigate these changes, but understanding that reflectivity and emissivity are susceptible to alteration as roofing materials age is crucial for effective roof performance assessment and energy efficiency.