Span Flat Roof Joist

Surveyors span tables for designing roof rafters.

Span flat roof joist.

Span is clear span between supports. 2 are indicated below. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. This is the distance between joist centres.

This demo version is fixed at 1m clear span. 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. 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. Dead load weight of structure and fixed loads 15 lbs ft 2.

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. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Maximum slop3 10 deg. 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.

Span calculator for wood joists and rafters also available for the android os. Also available for the android os. Usually 400 450 or 600mm but any value can be used up to 610mm max. 1 ft 0 3048 m.

Live load is weight of furniture wind snow and more. At least 40mm bearing on supports. Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope. 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.

1 enter joist details 1 1 span and joist spacing. For pitched roofs flat roofs and ceiling joists. 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. Flat roof joist calculator.

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Supporting imposed load for access and repair only. The full version allows any size. Joist breadth 47mm.