Flat Roof Rafter Span Chart

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

Flat roof rafter span chart.

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. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Dead load weight of structure and fixed loads 15 lbs ft 2. Surveyors span tables for designing roof rafters.

Span calculator for wood joists and rafters also available for the android os. 2 are indicated below. Roof pitch use recommended minimum roof pitches as specified by roof sheet supplier. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

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

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Live load is weight of furniture wind snow and more. 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. For pitched roofs flat roofs and ceiling joists.

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. Also available for the android os. 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.