Shed Roof Rafter Span Calculator

You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.

Shed roof rafter span calculator.

Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. If you look at the rafter span chart you ll notice that 2x4s can be used for rafters on spans up to 11. To calculate a shed roof select shed from the roof type dropdown list or click on the corresponding button on the toolbar to calculate a shed roof. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. Anything beyond that you are looking at using 2x6s for most sheds. 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. Half building width minus 1 2 ridge thickness.

Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. Span calculator for wood joists and rafters also available for the android os. 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. 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.

This calculator is to be used as an estimating tool only. Also available for the android os. Click the button to calculate the stock size needed for this job. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through.

See rafter run to outer wall calculator below. Input the rafter span on the flat eave overhang and pitch of the roof. Allow for ridge thickness when determining rafter run to outer wall.