Click the button to calculate the stock size needed for this job.
Roof rafter span lengths.
Use our online rafter length calculator to quickly compute the length of the shed roof rafter by entering the measurements of overhead length of roof span pitch or angle.
For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.
Here the number is 941 86 inches.
Determine the camber along the timbers length.
Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.
Mark the plumb cuts.
Marking out the roof rafter lengths onto the timber before cutting step 1.
This calculator is to be used as an estimating tool only.
Here the number is 1166 66 inches.
Rafter length using angle v r 2cos a rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch.
Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.
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.
With the tape measure hooked onto the top end transfer your two rafter lengths onto.
Input the rafter span on the flat eave overhang and pitch of the roof.