Tables assume a minimum c16.
Flat roof joist sizes c16.
It s often chosen as the standard timber for roof extensions or joist refurbishment as it s the most cost effective internal structural timber.
Section mm length availability metres imperial metric.
Sawn c16 and easy edge timber.
400mm 450mm 600mm 97 x 47 1 84 1 81 1 74 122 x 47 2 43 2 38 2 27 147 x 47 3 08 3 02 2 87 170 x 47 3 74 3 67 3 46 195 x 47 4 41 4 31 4 07 220 x 47 5 08 4 96 4 67.
These spans were calculated using our flat roof joist calculation.
Spacing in exterior exposure.
4 22 inc vat per metre.
This span table is to the format and methodology given in bs 5268 7 2.
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.
Surveyors span tables for designing roof rafters.
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.
Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres.
3 0 3 6 4 2 4 8 5 4 6 0.
Span calculator for wood joists and rafters available for the iphone.
Click on a span to generate a full calculation you can adjust the exact span.
C16 easy edge c16 j joist.
Fsc standard kiln dried regularised c16 treated carcassing 195 x 45mm.
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.
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Timber is supplied in metric sizes.
Live load psf dead load psf span calculator for wood joists and rafters.
Fsc standard kiln dried regularised c16 treated carcassing 220 x 45mm.
