Roof Joist Span Table

Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.

Roof joist span table.

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. Surveyors span tables for designing roof rafters. Also available for the android os.

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. Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor. 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 lesser grades spans should be shorter.

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. For other grades and species and for other loading conditions refer to the awc stjr. The figures are based on quality materials.

Span calculator for wood joists and rafters also available for the android os. The tables below give maximum spans for rafters and beams. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. 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. Spans for ceiling joists shall be in accordance with tables r802 4 1 and r802 4 2. Joist span tables use these tables to determine lengths sizes and spacing of 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.

If this is the case with your structure use the floor joist table to determine maximum joist length load.