Flat Roof Rafter Span Chart

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

Flat roof rafter span chart.

Also available for the android os. 1 ft 0 3048 m. Wood beam calculator american wood council website rafter and joist span faq. 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. 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. Dead load weight of structure and fixed loads 15 lbs ft 2.

For pitched roofs flat roofs and ceiling joists. 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. 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. 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.

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. Surveyors span tables for designing roof rafters. 2 are indicated below. For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine.

1 psf lb f ft 2 47 88 n m 2. The lengths and sizes of joists vary depending on the species and quality of the lumber used. Roof pitch use recommended minimum roof pitches as specified by roof sheet supplier. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.