Roof Rafter Size Table

It is always better to have a large rafter rather than be concerned with a sagging roof.

Roof rafter size table.

For pitched roofs flat roofs and ceiling joists. 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. 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. Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Click the button to calculate the stock size needed for this job. This calculator is to be used as an estimating tool only.