Roof Ridge Beam Span Calculator

Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.

Roof ridge beam span calculator.

Refer to sfpa s publication southern pine headers beams download in publications that includes all size selection and allowable load tables. For each application a pdf download is available. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Most interior beams need to include the roof load.

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. Use this common rafter caclulator by entering the span the roof pitch and the ridge thickness. Enter these values and these results are automatically fired the length of the rafter the run the rise and the height of the scaffold. If there is are any questions about anything else then you should contact your supplier or an engineer.

This calculator matches up with 90 of the applications in the 2012 international residential code book. If you are calculating rafter length from the center of the ridge beam as shown below you will need to subtract half of the thickness of the ridge beam from the top end of the rafter. For example if the ridge beam is 1 5 inches thick subtract 3 4 of an inch from the overall rafter length. Structural ridge beam span calculator posted on april 7 2020 by sandra rafter to ridge beam connection framing roof ceiling construction structural ridge beam absolute deflection in a ridge beam structural ridge beam tricks of the trade.

Also see assumptions for table development. It has been my experience to never use a beam smaller than a two ply 2 x 8. Loading conditions are detailed below.