Flat Roof Rafter Span Table

Should refer to trada document span tables for solid timber members in floors ceilings and roofs excluding trussed rafter roofs for dwellings or ask your lbc surveyor for advice.

Flat roof rafter span table. Therefore for gable roofed sheds the rafter span table is indicating how far a rafter can span half of your shed s width. Flat roof span tables allow for a maximum roof pitch of 5º. Surveyors span tables for designing roof rafters. Posts these span tables are designed for a minimum post size of 50 x 50 x 2 5mm up to a maximum height of 3 0m.

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. Loads are calculated in accordance with table 3 1 of as nzs 1170 1 2002. Use recommended minimum roof pitches as specified by roof sheet supplier. This is set by the roof use you selected in the previous screen and cannot be modified.

Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. 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 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. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Also available for the android os. If you have a single sloped roof then the 11 span distance for 2 4 rafters o c.

Spantec has prepared these tables for use by people skilled in the design and specification of the. 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. 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. Span calculator for wood joists and rafters also available for the android os.

The imposed uniformly distributed live load in the main span.