Rafter Span Flat Roof Joist Span Tables

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 span flat roof joist span tables.

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. Flat roof span tables allow for a maximum roof pitch of 5º. 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.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. Span tables for jois ts and rafters american wood council 4 span tables for joists and rafters american wood council design criteria. 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. For pitched roofs flat roofs and ceiling joists.

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. 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. Limited to span in inches divided by 360. 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. Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Deflection for 30 psf live load. These span tables apply only to flat roof and roof with a slope of up to 10 degrees.