Flat Roof Joist Span Chart

Also available for the android os.

Flat roof joist span chart.

1 enter joist details 1 1 span and joist spacing. Usually 400 450 or 600mm but any value can be used up to 610mm max. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Span calculator for wood joists and rafters also available for the android os.

Roof rafter span use this table to determine the maximum lengths of roof rafters. This is the distance between joist centres. Maximum clear span of flat roof joists in metres for sc3 timber spacing between joists size of roof joist 400mm 450mm 600mm 47 x 97 1 84 1 81 1 74 47 x 120 2 43 2 39 2 27 47 x 145 3 08 3 02 2 87 47 x 170 3 75 3 67 3 42 47 x 195 4 41 4 31 3 92 47 x 220 5 04 4 85 4 41 75 x 170 4 50 4 38 3 99. 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.

The full version allows any size. 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. Use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.