Which of the following materials is NOT commonly used for rigid roofing?

Wood is not commonly classified as a material for rigid roofing, which typically refers to materials that provide structural support and durability for the roof. Rigid roofing materials are usually made from substances that resist heavy weather conditions and contribute to the overall longevity of the roofing system.

Copper, fiberglass, and slate all fit into the category of rigid materials and are known for their strength and resistance to various environmental factors. Copper is often used for its longevity and aesthetic appeal, while fiberglass offers lightweight yet strong properties. Slate, being a natural stone, is recognized for its durability and outstanding lifespan.

In contrast, wood is more often used in roofing frameworks or as part of the underlying structure rather than the actual roofing surface itself. While treated wood can be used in certain roofing applications, it is typically not considered a rigid roofing material in the same way as the other listed options.