In roofing terminology, what differentiates a "cap sheet" from a "base sheet"?

In roofing terminology, the differentiation between a cap sheet and a base sheet primarily lies in their functions within a roofing system. The cap sheet serves as the top layer, providing essential protection to the underlying layers against environmental elements, such as water, sunlight, and physical wear. It is typically made of more durable materials to enhance its resistance to these factors. Furthermore, the cap sheet may also offer aesthetic benefits, depending on its design and color.

On the other hand, the base sheet is specifically designed to provide stability and support for the entire roofing assembly. It serves as a foundation layer to which the cap sheet and other materials are added. The base sheet helps in distributing weight and managing the stresses imposed on the roofing system, ensuring its integrity over time.

The other options regarding color and design, weight, or cost do not accurately reflect the primary functional difference between a cap sheet and a base sheet, making the correct answer focused on their roles within the roofing system.