Rafter Span Flat Roof Joist Span Tables

Surveyors span tables for designing roof rafters.

Rafter span flat roof joist span tables. 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. 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. 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. Span tables for jois ts and rafters american wood council 4 span tables for joists and rafters american wood council design criteria.

For pitched roofs flat roofs and ceiling joists. Limited to span in inches divided by 360. 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. 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.

Flat roof span tables allow for a maximum roof pitch of 5º. 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. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. 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.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Roof pitch use recommended minimum roof pitches as specified by roof sheet supplier. Deflection for 30 psf live load.