Span calculator for wood joists and rafters also available for the android os.
Shed roof rafter span calculator.
Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.
The preview window displays a dimensioned side view of the shed roof.
This calculator is to be used as an estimating tool only.
Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof.
Input the rafter span on the flat eave overhang and pitch of the roof.
The run for a lean to shed rafter ending into a wall should account for the ridge board nailed into the wall where the tops of the rafters rest into.
In other words if there is a 1 1 2 ridge board nailed into the wall and the width of the lean to is 96 then the run will be 94 1 2 96 1 1 2 94 1 2.
Click the button to calculate the stock size needed for this job.