How To Figure Roof Pitch And Rafter Length

Use a tape measure to measure the entire width of your building.

How to figure roof pitch and rafter length.

Roof pitch is simply the slopecreated by the rafter. The rafter member will be longer. It varies depending on culture climate style and available materials. Use the blueprints to establish a pitch for the roof.

For example a roof that rises 6 inches for every 12 inches of horizontal run has a 6 12 pitch. The angle or pitch of a roof is calculated by the number of inches it rises vertically for every 12 inches it extends horizontally. If you plan to have overhang etc. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement.

Determine a thickness for the ridge and use the drop down to select it. Before you start cutting you first need to determine how long your roof rafters need to be and the angles at which you ll cut the top and bottom of the rafter. For example if the roof rises 4 feet and the span is 16 feet twice the run then the pitch is 4 16 or 1 4. Roof pitch is designated by a set of numbers such as 4 12 or 6 12.

Use our online rafter length calculator to quickly compute the length of the shed roof rafter by entering the measurements of overhead length of roof span pitch or angle. Select a roof pitch. As aforementioned there is no standard pitch of a roof. For example a rafter installed at a 4 12 pitch rises 4 feet for every 12 feet from an outside wall.

Express roof pitch as the ratio of the amount of the vertical rise of a roof or rise over the corresponding horizontal distance or run you write the pitch assuming a run of 12 inches thus the ratio would describe how much a roof rises for each foot of the run. Measure as precisely as possible down to the 1 4 inch 0 64 cm 1 8 inch 0 32 cm or 1 16 inch 0 16 cm. It can be assessed in two ways either as the angle the rafter makes with the horizontal or the proportion between the rise and the run of the roof. Pitch is the incline of the roof represented as the ratio of rise to the span twice the run.

There is no standard universal pitch of roof. Includes result for hip valley factor slope factor and the roof slope in degrees. The results are automatically fired as soon as any of the values are entered or altered. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.

Roof pitch is often expressed as a ratio between rise and run in the form of x 12. The first number represent the amount in feet that a rafter rises. The length of the rafter is given from the long point of the ridge cut at the top down along the top edge the board to the same plumb cut on the rafter s notch. Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof.