What does R-value measure in roofing materials?

R-value is a measure specifically related to the thermal resistance of materials, which indicates how well a roofing material insulates against heat flow. A higher R-value signifies better insulating properties, meaning the material is more effective at resisting heat transfer. This is particularly important in roofing applications because effective insulation contributes to energy efficiency in a building. Proper insulation helps maintain temperature control within the structure, ultimately reducing heating and cooling costs and improving comfort levels.

While other options touch on characteristics of roofing materials, they do not relate to the R-value. The weight of roofing materials, their cost-effectiveness, or their durability are not captured by the R-value metric. Each of these aspects serves a different purpose in evaluating a roofing material but does not directly pertain to its thermal resistance or insulation effectiveness, which is the core of what R-value represents.