Roof Rafter Layout

In the gable roof example shown here a rafter with 6 in 12 pitch rises 6 in.

Roof rafter layout.

Draw a line down the edge of the tongue as shown in illustration b of the roof layout. Run is the horizontal distance that the rafter covers. Measure up a distance equal to 25 of the width of the rafter as shown in illustration c and put a mark. Another option are 2 x 8 rafters spaced 24 inches o c.

Let s use this example and find a size of rafter that will work. Looking through the center of the table we can find a couple of options. Here the number is 1166 66 inches. For every foot of run.

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. Once you know the pitch and the total run you can lay out the cuts of the rafter in a number of ways. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. 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.

There is no standard spacing it depends on what size of rafters you want to use and the span of your shed. For standard shed roof rafter spacing see rafter span chart. For instance 2 grade 2x4s at 16 on center will span just over 9. Flip the square over and place the tongue along the line made in illustration b.

Marking the birdsmouth and the ridge board setback.