Roof Cuts And Rafter Lengths

Print full scale rafter plumb cut templates and birdsmouth templates fold template over rafter to mark or cut through.

Roof cuts and rafter lengths.

With calculations diagrams and tables. Roof cuts and rafter lengths hancock s 10th edition is a very popular best selling book. Given here are the formulae to calculate the length of a shed roof rafter to make your roofings stronger and look beautiful. The roof rafters provide integral structural support to 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 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. The rafter member will be longer. These are used in almost every roof including a gable end roof lean to roof and hipped roof as well.

See rafter run to outer wall calculator below. It is the length of this portion of the rafter. It will help you with plumb and side cuts for hip and rafter down and side purlin cuts and more. The results are automatically fired as soon as any of the values are entered or altered.

Note that this is not the actual length of the rafter. This 88 page pocket size edition is in metric updating all the old calculations and it is a very easy. Determine a thickness for the ridge and use the drop down to select it. 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.

Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Half building width minus 1 2 ridge thickness. When you cut the rafters you ll need to make 3 separate cuts. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

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. If you plan to have overhang etc. For example if the roof rises 4 feet and the span is 16 feet twice the run. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.

Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter. 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. Select a roof pitch. Allow for ridge thickness when determining rafter run to outer wall.

Calculations for roof frames roof cuts and rafter lengths. Includes result for hip valley factor slope factor and the roof slope in degrees.