Roof Cuts And Rafter Lengths

Determine the camber along the timbers length.

Roof cuts and rafter lengths.

Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. 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. 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. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

Roof cuts rafter lengths roofing book. 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. With the tape measure hooked onto the top end transfer your two rafter lengths onto. See rafter run to outer wall calculator below.

This is the horizontal measurement from the outside of the wall to the inside of the ridge. Print full scale rafter plumb cut templates and birdsmouth templates fold template over rafter to mark or cut through. For example if the ridge beam is 1 5 inches thick subtract 3 4 of an inch from the overall rafter length. The next result is the run.

Allow for ridge thickness when determining rafter run to outer wall. It will help you with plumb and side cuts for hip and rafter down and side purlin cuts and more. Rafter book page 1 created date. Before you can mark the rafter lengths and layout check the.

Half building width minus 1 2 ridge thickness. 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. Marking out the roof rafter lengths onto the timber before cutting step 1.

With calculations diagrams and tables. 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. Rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.