Roof Cuts And Rafter Lengths

Roof cuts and rafter lengths hancock s 10th edition is a very popular best selling book.

Roof cuts and rafter lengths. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. It will help you with plumb and side cuts for hip and rafter down and side purlin cuts and more. 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.

Marking out the roof rafter lengths onto the timber before cutting step 1. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. 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. 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.

See rafter run to outer wall calculator below. For example if the ridge beam is 1 5 inches thick subtract 3 4 of an inch from the overall rafter length. Roof cuts rafter lengths roofing book. If you are calculating rafter length from the center of the ridge beam as shown below you will need to subtract half of the thickness of the ridge beam from the top end of the rafter.

Determine the camber along the timbers length. Includes result for hip valley factor slope factor and the roof slope in degrees. This is the horizontal measurement from the outside of the wall to the inside of the ridge. The next result is the run.

Rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. Rafter book page 1 created date. Allow for ridge thickness when determining rafter run to outer wall. With the tape measure hooked onto the top end transfer your two rafter lengths onto.

Mark the plumb cuts. 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. With calculations diagrams and tables. Before you can mark the rafter lengths and layout check the.