Span Flat Roof Joist

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.

Span flat roof joist.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. 2 are indicated below. Maximum slop3 10 deg. This is the distance between joist centres.

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. Flat roof joist calculator. 1 enter joist details 1 1 span and joist spacing. Surveyors span tables for designing 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. Usually 400 450 or 600mm but any value can be used up to 610mm max. Live load is weight of furniture wind snow and more. The full version allows any size.

1 psf lb f ft 2 47 88 n m 2. Supporting imposed load for access and repair only. 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. 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.

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. Floor joists flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2. Joist breadth 47mm.

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. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Span calculator for wood joists and rafters also available for the android os. 1 ft 0 3048 m.

This demo version is fixed at 1m clear span. At least 40mm bearing on supports. 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.