Roof Rafter Layout

Once you know the pitch and the total run you can lay out the cuts of the rafter in a number of ways.

Roof rafter layout.

Marking the birdsmouth and the ridge board setback. There is no standard spacing it depends on what size of rafters you want to use and the span of your shed. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. Let s use this example and find a size of rafter that will work.

Run is the horizontal distance that the rafter covers. For every foot of run. Rafter run outer wall this should be measured starting from the center of the roof span and then extending to the very edge of the exterior wall. Draw a line down the edge of the tongue as shown in illustration b of the roof layout.

The table states that 2 x 6 rafters spaced 16 inches on center o c can span a maximum distance of 13 feet 5 inches. Measure up a distance equal to 25 of the width of the rafter as shown in illustration c and put a mark. For a gable roof the run is measured from the centerline of the ridge board to the outside edge of the top of the wall. To lay out a common rafter you need the pitch of the roof expressed in units of rise per foot of run.

Another option are 2 x 8 rafters spaced 24 inches o c. Here the number is 941 86 inches. Here the number is 1166 66 inches. For standard shed roof rafter spacing see rafter span chart.

Looking through the center of the table we can find a couple of options.