What angle is a score cut typically made relative to rafters/joists?

• A. 45° to Rafters/Joists
• B. 0°
• C. 90°
• D. 30°

Answer: (A)

A score cut is a shallow, guiding cut used to establish a predictable break line in the roof decking before making the full ventilation cut. Making this cut at about 45 degrees to the rafters/joists places the cut across the deck in a diagonal path, which helps the decking fail along the intended plane between the framing and provides a clear reference line for the deeper cut. This angle reduces the chance of snagging a rafter and promotes a cleaner, more controllable opening.

A cut made parallel to the rafters (0°) risks skimming along the surface without creating a proper guide line, while a cut that is perpendicular to the rafters (90°) or at a shallower 30° angle doesn’t provide the same balance of controllability and deck fracture guidance.