Roof Pitch Rafter Length Formula

Rafter length calculator calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement.

Roof pitch rafter length formula.

The rafter member will be longer. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. The length of rafter per meter of run is 1 1543. Includes result for hip valley factor slope factor and the roof slope in degrees.

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. Using the appropriate roof pitch table in a rafter cutting guide such as 4 12 determine the length of each rafter based on the correlating measurement shown for 7 feet. You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. 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 simply the slopecreated by the rafter. Roof pitch is often expressed as a ratio between rise and run in the form of x 12. Note that this is not the actual length of the rafter. In this example the shorter walls are 14 feet long.

Select a roof pitch. Determine a thickness for the ridge and use the drop down to select it. Rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. It is the length of this portion of the rafter.

All we do now is use a calculator to multiply 1 610 by the measurement in the book. Use the blueprints to establish a pitch for the roof. Roof pitch refers to the slope which the rafter creates. All you need to know are the span of the building and the slope of the roof.

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. 1 1543 x 1 610 1 858m. This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m. 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.

Pitch is the incline of the roof represented as the ratio of rise to the span twice the run. The results are automatically fired as soon as any of the values are entered or altered. Divide this in half and the result is 7 feet.