On a flat roof with built-up roofing, which base can be used?

In the context of flat roofing systems, particularly those with built-up roofing (BUR), a variety of base materials can serve as a foundation for the roofing layers. The correct choice highlights that multiple materials, including wood, concrete, and metal, can be utilized as a base for built-up roofing systems.

Wood is often employed due to its lightweight properties and ease of installation. It also has good thermal and acoustic insulation qualities. However, it's essential that the wood is treated to withstand moisture since it can be susceptible to decay over time if not properly protected.

Concrete provides a solid and durable base that can support heavy roofing systems. It is non-combustible and offers excellent resistance to water infiltration when properly sealed, making it a suitable option for BUR systems.

Metal bases can also be beneficial, particularly in industrial settings where additional durability is necessary. They can provide a strong, lightweight alternative and can be beneficial in preventing certain types of damage, such as from pests or environmental elements.

Each of these materials contributes to the stability, durability, and performance of the flat roof, making the choice of a base material flexible depending on the specific requirements and conditions of the installation. This diversity in material options is important, as it allows builders and contractors to select the