What does performing a Blow Out/Drop Cut involve?

• A. Cutting only the decking material away
• B. Cutting through the roof sheathing to create a large opening
• C. Drilling holes through rafters to relieve pressure
• D. Intentionally cutting through a rafter/joist as part of ventilation

Answer: (D)

Vertical ventilation aims to release heat and smoke by creating a roof opening. Blow-out/drop cut is a technique where you deliberately cut through a structural member—typically a rafter or joist—to produce a large opening quickly. This controlled removal of a roof member creates a substantial vent path for heat and smoke, which helps improve visibility and conditions for firefighters inside. It’s distinct from merely removing decking or roof sheathing, which doesn’t involve taking out a structural member and may not yield the same sized opening or airflow path. Drilling holes through rafters isn’t used to establish a proper vent and can weaken the structure, so the action described in this cut is specifically about cutting through a rafter/joist as part of ventilation.