A carpenter is tasked with estimating materials for a roof truss package for a complex hip roof. The truss manufacturer provides a detailed layout with individual truss types and quantities. Which of the following is the most significant risk to the material estimate if the carpenter only reviews the quantity schedule provided by the manufacturer without cross-referencing it with the architectural drawings and local building codes (e.g., NBC 2015, provincial amendments)?

Question: A carpenter is tasked with estimating materials for a roof truss package for a complex hip roof. The truss manufacturer provides a detailed layout with individual truss types and quantities. Which of the following is the most significant risk to the material estimate if the carpenter only reviews the quantity schedule provided by the manufacturer without cross-referencing it with the architectural drawings and local building codes (e.g., NBC 2015, provincial amendments)?

Answer options:

• An overestimation of sheathing plywood due to standard rectangular roof area calculations. ✅ Failure to account for specialized fasteners or hurricane clips required by local wind load requirements.
• Underestimation of labour hours for truss installation.
• Higher-than-expected waste factor for fascia and frieze boards.

Correct answer: Failure to account for specialized fasteners or hurricane clips required by local wind load requirements.

Explanation: While the manufacturer provides the trusses, local building codes and specific site conditions (like high wind zones) often dictate the use of specialized fasteners, bracing, or hurricane clips. Relying solely on the truss manufacturer's schedule might miss these code-mandated items, leading to an underestimation of critical supplementary materials. The other options are less directly impacted by code review for a pre-engineered truss package.