Roof Joist Size Table

If this is the case with your structure use the floor joist table to determine maximum joist length load.

Roof joist size table.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. For pitched roofs flat roofs and ceiling joists. For uninhabitable attics without storage we will use table r802 4 1 and for uninhabitable attic with limited storage we will use table r802 4 2. Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists.

Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. 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. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.

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. 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. Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor. 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.