Roof Pitch Rafter Length Formula

Note that this is not the actual length of the rafter.

Roof pitch rafter length formula.

Use the blueprints to establish a pitch for the roof. Roof pitch refers to the slope which the rafter creates. Rafter length calculator calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. 1 1543 x 1 610 1 858m.

If you plan to have overhang etc. All you need to know are the span of the building and the slope of the roof. Determine a thickness for the ridge and use the drop down to select it. In this example the shorter walls are 14 feet long.

When building a roof how do you calculate the length of the rafters. All we do now is use a calculator to multiply 1 610 by the measurement in the book. Roof pitch is simply the slopecreated by the rafter. The length of rafter per meter of run is 1 1543.

Often you express roof pitch as the ratio between the rise and the run in the form of x 12. Rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m. 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.

Pitch is the incline of the roof represented as the ratio of rise to the span twice the run. The rafter member will be longer. 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. Divide this in half and the result is 7 feet.

Select a roof pitch. 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. 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.

Roof pitch is often expressed as a ratio between rise and run in the form of x 12. The results are automatically fired as soon as any of the values are entered or altered. Includes result for hip valley factor slope factor and the roof slope in degrees.