For a building with a plain gable roof, if the common rafter length is 14' and the ridge is 30', how many full bundles of wood shingles are required after adding 10% waste?

To determine the number of bundles of wood shingles required, first, one needs to calculate the total roof area that needs to be covered. In this case, with a plain gable roof, the area can be calculated based on the dimensions provided: the length of the common rafter and the width.

1. Calculate the total roof area: The common rafter length of 14' represents how far the roof slopes down to the eave from the ridge, which is the vertical height or is part of the triangular gable. The ridge length of 30' serves as the horizontal length of the gable roof. Therefore, the total area for one side of the gable roof is found using the formula for the area of a triangle (0.5 × base × height). However, since there are two sides to a gable roof, we eventually need to double this area.

For illustrative calculations:

[

\text{Area of one side} = \frac{1}{2} \times \text{ridge length} \times \text{common rafter length}

]

[

\text{Area of one side} = \frac{1}{2} \times 30