Rafter Span Flat Roof Joist Span Tables

Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.

Rafter span flat roof joist span tables.

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. Use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. View joist rafter tables.

The figures are based on quality materials. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter.

Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Straight line interpolation shall be permitted for intermediate spans and design values. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.

Dead load weight of structure and fixed loads 15 lbs ft 2. These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center. 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. The tables below give maximum spans for rafters and beams.

Also available for the android os. For pitched roofs flat roofs and ceiling joists. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. 1 psf lb f ft 2 47 88 n m 2.

Span calculator for wood joists and rafters also available for the android os. Live load is weight of furniture wind snow and more. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.