Flat Roof Rafter Span Tables Uk

Span is clear span between supports.

Flat roof rafter span tables uk.

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. Plasterboard on the underside of the rafter. Maximum slop3 10 deg. Surveyors span tables for designing roof rafters.

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. At least 40mm bearing on supports. 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. This is the distance between rafter centres.

Refer to approved document to part a of the building regulations on gov uk for heavier roofing materials or unusual loading conditions these tables may not be appropriate. Flat roof joists rafters purlin span tables rafters. Span tables for rafters to bs 5268 7 5 imposed loads of 0 75 kn m snow load are applicable to most areas where the altitude does not exceed 100. Flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2.

For pitched roofs flat roofs and ceiling joists. Supporting imposed load for access and repair only. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees. 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.

Also available for the android os. Contact a building control officer for advice. 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. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.

Joist breadth 47mm. Span calculator for wood joists and rafters also available for the android os. 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.