Spike's Calculators

# Calculate the Amount of Siding to Cover a Gable

A gable in this example is the triangular portion of a wall that sits under the two sides of a sloped roof overhang.

##### Example
```Building width = 24 feet
Gable height = 6 feet```

The square footage of the gable (green area);
`6  *  24 ÷  2 = 72`
`The gable has an area of 72 square feet.`

The siding we are using in this example is Fibre-cement board, 144 inches long and 8 1/4-inch wide. It is installed with a 1 1/4-inch overlap, giving it an exposed face of seven inches.

##### Lineal foot factor

Calculate the lineal foot factor of your siding.

To get the lineal foot factor, divide the exposed face amount of your siding by 12; (this calculates the number of rows in 12 inches)

`12 ÷ 7 = 1.743`
`This siding has a lineal foot factor of 1.743.`

Multiply the square footage of the gable of 72 square feet by 1.743. The result is the number of boards in lineal feet;

`72 * 1.743 = 123.43 rounded to 124`
`You will need 124 lineal feet of siding`

##### Convert the lineal feet to the number of boards;

144 inches = 12 feet. The boards are 12 feet long. Divide the lineal feet amount by 12 to get the number of boards needed;

`124 / 12 = 10.333`
`Ideally, it would take ten and one-third lengths of boards to cover this gable.`

Placing the boards on the gable and counting the full boards used, we come to 11 full boards to cover this gable, and there is approximately 10% waste.