Roof Joist Span Table

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.

Roof joist span table.

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. If this is the case with your structure use the floor joist table to determine maximum joist length load. Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists.

Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. The figures are based on quality materials. Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.

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. Span calculator for wood joists and rafters also available for the android os. For other grades and species and for other loading conditions refer to the awc stjr. Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. The tables below give maximum spans for rafters and beams. Also available for the android os. Table r802 4 1 ceiling joist spans for common lumber species uninhabitable attics without storage live load 10 psf l δ 240.

View joist rafter tables. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. Surveyors span tables for designing roof rafters. Keep in mind that these are maximums in other words shortening spans slightly will result in a more solid structure.

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.