Rafter Span Roof Joist Span Chart

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.

Rafter span roof joist span chart.

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. Span calculator for wood joists and rafters also available for the android os. Surveyors span tables for designing roof rafters. Span tables for joists and rafters 3 american wood council table 9 1 required compression perpendicular to grain design values f c in pounds per square inch for simple span joists and rafters with uniform load.

Span tables for flat roof joists to bs 5268 7 2 imposed loads of 0 75 kn m for maintenance and snow load are applicable where there is no permanent access no fixed ladder or staircase and most areas where the altitude does not exceed 100 metres refer to bs 6399 3. For pitched roofs flat roofs and ceiling joists. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.