Roof Rafter Layout

Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak.

Roof rafter layout.

Run is the horizontal distance that the rafter covers. For instance 2 grade 2x4s at 16 on center will span just over 9. Here the number is 941 86 inches. Let s use this example and find a size of rafter that will work.

For every foot of run. Flip the square over and place the tongue along the line made in illustration b. Looking through the center of the table we can find a couple of options. There is no standard spacing it depends on what size of rafters you want to use and the span of your shed.

Once you know the pitch and the total run you can lay out the cuts of the rafter in a number of ways. For standard shed roof rafter spacing see rafter span chart. Marking the birdsmouth and the ridge board setback. 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.

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. In the gable roof example shown here a rafter with 6 in 12 pitch rises 6 in. Measure up a distance equal to 25 of the width of the rafter as shown in illustration c and put a mark. Draw a line down the edge of the tongue as shown in illustration b of the roof layout.

Here the number is 1166 66 inches.