Span tables for solid timber joists.
C24 flat roof joist span.
Surveyors span tables for designing roof rafters.
Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.
Stocked at all branches click here to download c24 strength class pdf document.
Span tables for flat roof joists to bs 5268 7 2 imposed loads of 0 75 kn m for maintenance and snow load are applicable where there is no permanent access no fixed ladder or staircase and most areas where the altitude does not exceed 100 metres refer to bs 6399 3.
For pitched roofs flat roofs and ceiling joists.
Click here to download c16 span table leaflet c24 span table our premium grade of carcassing is c24 graded.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
C16 span table only stocked at our mitcham depot.
This table is for a dead load of more than 0 25 but not more than 0 50 and allows for an imposed loading of no more than 1 5 kn sq m.
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.
Floor joist span tables for surveyors floor construction.
Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.
These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
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.
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.
Maximum clear span of flat roof joists in metres for sc3 timber spacing between joists size of roof joist 400mm 450mm 600mm 47 x 97 1 84 1 81 1 74 47 x 120 2 43 2 39 2 27 47 x 145 3 08 3 02 2 87 47 x 170 3 75 3 67 3 42 47 x 195 4 41 4 31 3 92 47 x 220 5 04 4 85 4 41 75 x 170 4 50 4 38 3 99.
Unless c24 timber is specified the more generally used timbers are less expensive c16.
