What is the approved method of attaching the base layer of built-up roofing material?

What is the approved method of attaching the base layer of built-up roofing material?

• A. Nail (mechanical fasteners)
• B. torch down
• C. hot mop
• D. no fasteners

Answer: (A)

In built-up roofing, the base sheet must be secured to the roof deck so it won’t shift or lift as the other plies are applied and in windy conditions. The approved way to do this is to use mechanical fasteners—nails designed for roofing with appropriate washers—to hold the base sheet firmly to the deck. This provides immediate anchorage and stability during the rest of the installation and in service. Torch-down is a different method used for torch-applied membranes, and hot mop is a bonding method for applying asphalt, but neither replaces the need to mechanically fasten the base sheet in many BUR installations. Leaving the base layer unattached (no fasteners) would result in movement and potential leaks.

In built-up roofing, the base sheet must be secured to the roof deck so it won’t shift or lift as the other plies are applied and in windy conditions. The approved way to do this is to use mechanical fasteners—nails designed for roofing with appropriate washers—to hold the base sheet firmly to the deck. This provides immediate anchorage and stability during the rest of the installation and in service.

Torch-down is a different method used for torch-applied membranes, and hot mop is a bonding method for applying asphalt, but neither replaces the need to mechanically fasten the base sheet in many BUR installations. Leaving the base layer unattached (no fasteners) would result in movement and potential leaks.