How is the net roof area estimate calculated?

The net roof area estimate is calculated by adding together the square footage from different sections of the roof—typically referred to as Box 1 and Box 2—and then multiplying that sum by a slope factor to adjust for the pitch of the roof. The slope factor acknowledges that steeper roofs present more surface area than flat roofs due to their angle.

In this case, option A accurately represents that process. It begins by summing up the areas of the designated boxes, reflecting a comprehensive view of the roof's different sections. The subsequent multiplication by the slope factor ensures that the estimated area takes into account the actual surface area that will require roofing material, which can vary greatly depending on the slope.

The other options do not align with the accepted methodology for calculating net roof area; they either incorrectly incorporate addition, subtraction, or division in ways that do not reflect the requirement to adjust for roof pitch accurately. By utilizing both the total area and slope factor multiplication, option A provides a correct and practical approach for estimating the net roof area in roofing calculations.