How To Roof Rafters

If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.

How to roof rafters.

If you re framing a gable roof on a new house or building a shed or even a doghouse with a gable roof you ll need to cut a number of roof rafters. The first step in building the roof rafters is to cut one rafter board to length with the ends angled properly and then to mark and cut the birds mouth and seat on the rafter. The ridge end of the rafter and often the eve end will need to be cut to the angle of the roof slope. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. The roof on this shed is a 4 in 12 slope which makes it a 18 and. The boards creating the slope of the roof are wider than lumber used to build trusses 2x8s 2x10s and 2x12s are most common in rafters vs. There is no standard spacing it depends on what size of rafters you want to use and the span of your shed.

If you get premium kiln dried lumber then you could span 10 5 with the same size of lumber and. Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter. Includes result for hip valley factor slope factor and the roof slope in degrees. Framing a roof is the last step in framing new construction.

Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. Rafter boards are fastened to the ridge board at the peak and the top plate where they join the wall. For standard shed roof rafter spacing see rafter span chart. The roof rafters provide integral structural support to the roof.

For instance 2 grade 2x4s at 16 on center will span just over 9. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.