Johnson Level & Tool Mfg. RAS-1 User Manual

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FIG. 4 Common Rafter Layout.

length. For our rafter we get 15' 7-1/2". This is the rafter length

from the top cut to the seat plumb mark (see Figure 4).
NOTE: For a run greater than that given in the tables,

simply add any two runs that will equal the run desired.

Then find the lengths for those two rafters and add them

together. For example, say that your run is 38', add the

length for a 18' run and the length for a 20' run together.

Or add a 15' run’s length and a 23' run’s length together.
TAIL OR EAVE LENGTH: The tail or eave overhang now

must be added to the rafter length (see Figure 5 for sug-

gested eave construction). With our example, let us use