Flat Roof Rafter Span Chart

Wood beam calculator american wood council website rafter and joist span faq.

Flat roof rafter span chart.

For pitched roofs flat roofs and ceiling joists. 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. Flat roof span tables allow for a maximum roof pitch of 5º. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

The lengths and sizes of joists vary depending on the species and quality of the lumber used. Dead load weight of structure and fixed loads 15 lbs ft 2. Roof pitch use recommended minimum roof pitches as specified by roof sheet supplier. 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.

Live load is weight of furniture wind snow and more. Span calculator for wood joists and rafters also available for the android os. 2 are indicated below. 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.

Also available for the android os. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. 1 ft 0 3048 m. 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.

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. 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. 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.