What is crucial to apply while the bitumen is hot for proper adhesion in a flood coat?

• A. The stone aggregate
• B. A protective membrane
• C. A layer of insulation
• D. A sealer coat

Answer: (A)

The correct answer highlights the importance of applying stone aggregate while the bitumen is hot in order to achieve proper adhesion in a flood coat. When bitumen is heated, it becomes more viscous and adhesive, allowing the aggregate to bond effectively. This process ensures that the stone is embedded into the bitumen, creating a strong, durable surface that enhances the overall performance of the roofing system.

This application also serves multiple functions, such as protecting the bitumen from UV rays, improving the roof's aesthetic appearance, and contributing to the longevity of the roofing material. Therefore, applying the stone aggregate in a hot state is essential for maintaining the efficacy and integrity of the built-up roofing system.