Roof Joist Size Table

Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists.

Roof joist size table.

As mentioned above the span tables within the code list the allowable ceiling joist spans for common lumber sizes based on what design load scenario is applied. Surveyors span tables for designing roof rafters. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Ceiling 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. If this is the case with your structure use the floor joist table to determine maximum joist length load. For pitched roofs flat roofs and ceiling joists. Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor.