Flat Roof Joist Span Chart

Roof rafter span use this table to determine the maximum lengths of roof rafters.

Flat roof joist span chart.

Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. Use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.

This is the distance between joist centres. 1 enter joist details 1 1 span and joist spacing. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. For roof live loads of 12 psf or 16 psf table multiply tabulated multiply required number span by e value by 12 psf 16 psf 12 psf 16 psf r 1 1 17 1 07 0 96 0 99 r 5 1 14 1 06 0 89 0 96.

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. Spans and required e values tabulated for 20 psf shall be permitted to be adjusted in accordance with the fol lowing table. The full version allows any size.

Usually 400 450 or 600mm but any value can be used up to 610mm max. This demo version is fixed at 1m clear span.