Ceiling joist span tables.
Roof joist size table.
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 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.
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.
Surveyors span tables for designing roof rafters.
Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size.
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.
Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists.
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.
For pitched roofs flat roofs and ceiling joists.
These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor.
Size of joists mm clear span c16 joist m clear span c24 joist m 47 x 95 47 x 120 47 x 145 47 x 170 47 x 195 47 x 220 1 77 2 40 2 89 3 38 3 87 4 36 2 04 2 75 3 47 4 20 4 93 5 66 floor joists flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2.