Rafter Span Roof Joist Span Table

For each application a pdf download is available.

Rafter span roof joist span table.

For pitched roofs flat roofs and ceiling joists. Surveyors span tables for designing roof rafters. 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. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.

These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center. 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. Tables listing maximum spans for southern pine joists and rafters are detailed below. The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter.

Use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Straight line interpolation shall be permitted for intermediate spans and design values. These 46 tables are based upon design values for visually graded southern pine dimension lumber that became effective june 1 2013.