Horizontal grade roof cements are used for embedding metal flashing flanges and forming seals at what?

• A. Terminations
• B. Penetrations
• C. Joints between panels
• D. Edge details

Answer: (B)

Water can infiltrate most easily where something penetrates the roof surface, like pipes, vents, or drains. Horizontal grade roof cement is used around those penetrations to embed the flashing flange and fill gaps, creating a continuous, watertight seal between the flashing and the roof deck. This helps prevent leaks where the roof meets penetrations.

Other locations like terminations (roof edges), joints between panels (panel seams), or edge details require different flashing and sealing approaches, so this specific cement is chosen for penetrations where a secure, watertight seal around protrusions is essential.