What is a disadvantage of built-up roof systems using cool applied adhesives?

The choice highlighting that built-up roof systems using cool applied adhesives have minimal waterproofing and require a base layer is accurate because these systems rely on multiple layers of bitumen and reinforcing materials to create a durable, waterproof barrier. However, if the base layer is not properly installed or if insufficient care is taken during application, the effectiveness in providing waterproofing can be compromised. This necessitates the use of a reliable base layer, making it a critical aspect of the system's design and installation.

Understanding this is essential for roofing professionals, as prioritizing adequate waterproofing measures ensures longevity and effectiveness of the roof system. The other aspects, such as weight and structural support or heat retention, do not directly concern the adhesive's waterproofing quality or the fundamental requirements for constructing a built-up roof system.