Flat Roof Joist Span Chart

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.

Flat roof joist span chart.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. The full version allows any size. This is the distance between joist centres. Usually 400 450 or 600mm but any value can be used up to 610mm max.

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. Roof rafter span use this table to determine the maximum lengths of 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. Floor joist span use this table to determine the maximum lengths of floor 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. Span calculator for wood joists and rafters also available for the android os. 1 enter joist details 1 1 span and joist spacing. This demo version is fixed at 1m clear span.