Roof Joist Span Table

These span tables apply only to flat roof and roof with a slope of up to 10 degrees.

Roof joist span table. If this is the case with your structure use the floor joist table to determine maximum joist length load. The tables below give maximum spans for rafters and beams. For pitched roofs flat roofs and ceiling joists. For lesser grades spans should be shorter.

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. Spans for ceiling joists shall be in accordance with tables r802 4 1 and r802 4 2. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.

Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. For other grades and species and for other loading conditions refer to the awc stjr. Notches are not to exceed 0 125 of the depth of the joist and are to be located between 0 07 and 0 25 of the span from the support. View joist rafter tables.

Table r802 4 1 ceiling joist spans for common lumber species uninhabitable attics without storage live load 10 psf l δ 240. Span calculator for wood joists and rafters also available for the android os. Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists. Surveyors span tables for designing roof rafters.

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. Keep in mind that these are maximums in other words shortening spans slightly will result in a more solid structure. 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. Also available for the android os.

The figures are based on quality materials.