Which cut completes the ventilation hole?

• A. Skim Cut
• B. Head Cut
• C. Bottom Cut
• D. Parallel Cut

Answer: (C)

In vertical ventilation, you create the opening for exhaust by making a sequence of cuts that define a clean hole. The last cut finishes the opening along the lower edge, so the hole is complete and has a stable, unobstructed path for heat and smoke to escape. This bottom cut marks the final edge of the rectangle and ensures a clean, continuous opening.

The skim cut is the shallow, initial pass used to evaluate the roof and fire conditions before committing to larger cuts; it doesn’t finish the hole. The head cut is an early cut that starts the opening from the top edge but leaves the bottom edge incomplete. The parallel cut, by contrast, would create a cut along a side or line, but on its own it does not produce a finished hole. Completing with the bottom cut provides the proper, finished opening needed for effective ventilation.