Roof Cuts And Rafter Lengths

Select a roof pitch.

Roof cuts and rafter lengths. For example if the roof rises 4 feet and the span is 16 feet twice the run. It is the length of this portion of the rafter. Pitch is the incline of the roof represented as the ratio of rise to the span twice the run. 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.

Roof cuts and rafter lengths hancock s 10th edition is a very popular best selling book. 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. Determine a thickness for the ridge and use the drop down to select it. Half building width minus 1 2 ridge thickness.

Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. You are ready to set out and cut the common rafter lengths as soon as the wall plates have been squared levelled and fixed strapped down onto the brickwork. See rafter run to outer wall calculator below. If you plan to have overhang etc.

The ridge cut also called the plumb cut at the top of the rafter the birdsmouth cut. When you cut the rafters you ll need to make 3 separate cuts. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. These are used in almost every roof including a gable end roof lean to roof and hipped roof as well.

Includes result for hip valley factor slope factor and the roof slope in degrees. With calculations diagrams and tables. This 88 page pocket size edition is in metric updating all the old calculations and it is a very easy. Step 4 add the measurement for the overhang the eaves on the outside wall to the result obtained in the rafter guide to determine the overall rafter length.

It will help you with plumb and side cuts for hip and rafter down and side purlin cuts and more. Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter. Note that this is not the actual length of the rafter. Print full scale rafter plumb cut templates and birdsmouth templates fold template over rafter to mark or cut through.

The rafter member will be longer. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Given here are the formulae to calculate the length of a shed roof rafter to make your roofings stronger and look beautiful. While making roofing for your house with the roof rafters it is important to know the rafter length to make the roof seat perfectly on the rafter.

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. Allow for ridge thickness when determining rafter run to outer wall.