Roof Cuts And Rafter Lengths

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

Roof cuts and rafter lengths.

Marking out the roof rafter lengths onto the timber before cutting step 1. With the tape measure hooked onto the top end transfer your two rafter lengths onto. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. 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.

Includes result for hip valley factor slope factor and the roof slope in degrees. With calculations diagrams and tables. The next result is the run. 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.

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. 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. 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. Before you can mark the rafter lengths and layout check the. This is the horizontal measurement from the outside of the wall to the inside of the ridge. Half building width minus 1 2 ridge thickness.

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. Rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. Determine the camber along the timbers length. 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.

Roof cuts and rafter lengths hancock s 10th edition is a very popular best selling book. Mark the plumb cuts. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Rafter book page 1 created date.