Timber Roof Beam Span Tables

Simplified span tables for southern pine lumber and glued laminated timber glulam headers beams and girders.

Timber roof beam span tables.

Surveyors span tables for designing roof rafters. View joist rafter tables. Also available for the android os. View size selection tables.

The figures are based on quality materials. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Span calculator for wood joists and rafters also available for the android os. These span tables apply only to flat roof and roof with a slope of up to 10 degrees.

Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. View allowable load tables. Keep in mind that these are maximums in other words shortening spans slightly will result in a more solid structure.

Window door garage door headers supporting roof wall floor loads. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. 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. For lesser grades spans should be shorter.

Tables providing size selections for various beam spans and loading combinations for southern pine dimension lumber and southern pine glued laminated timber are available for the following applications. 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. Window door garage door headers supporting roof loads only.