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For hipped roofs where all sides have the same slope, the length of the top ridge is equal to the length of the roof plan minus the width, regardless of slope. Add 5% to all cappings to allow for laps.

## How do you calculate roof sheets for hip roof?

Estimate the number of sheets of plywood or OSB that are needed for sheathing a Hip roof. The calculation is based on 4′ x 8′ sheets = 32 square feet each.

## How do you calculate rafter length for a hip roof?

Divide the span of the roof by two to obtain the run of the roof. The span of the roof is 25 feet, so the run of the roof is 25 / 2 = 12.5 feet. Divide the run of the roof by the cosine of the angle of the roof to obtain the length of a common rafter.

## How is hip and valley roof calculated?

Hip and Valley Factor Formula

For a roof slope expressed as “X-in-12” (rise-in-run), the hip and valley factor is determined by finding the square root of ((rise/run)² + 2) for the slope of the adjacent roof sections. Divide the rise by the run (the run is 12).

## How do you calculate hip roof volume?

Find the volume of the two pyramids at once by using the base area you just calculated in the formula “1/3 times base area times height.” If the height is 10, then multiply 1/3 times 10 times 40 to get your total volume of 133.3 cubic feet.

## What is the slope of a hip roof?

The most common hip roof pitch ratios fall between 4:12 and 6:12, although variations occur based on factors such as snow, rain, and wind conditions, which is because steeper hip roof pitch ratios allow for less accumulations of snow and rain on the roof, and lower ratios provide less wind resistance.

## How do you calculate the volume of a roof space?

The simplest way to find the total volume of the enclosed attic is to break the calculation down into its constituent parts.

- Measure the width and length of the base area of the roof. …
- Measure the height of the roof peak from the top of the ceiling — the floor of the attic — to the ridge cap.

## How do you calculate the volume of a building?

Whereas the basic formula for the area of a rectangular shape is length × width, the basic formula for volume is length × width × height.

## How do you measure a pitched roof?

How to Calculate Roof Pitch in Degrees

- First, you need to measure the run of your roof. …
- Next, you need to figure out the rise. …
- Now, divide the rise by the run. …
- Then, divide 1 by your tangent.
- Finally, multiply this result by 180/π and you’ve calculated your roof pitch!