Flat Roof Timber Sizes

Here the number is 1166 66 inches.

Flat roof timber sizes. Where a new flat roof abuts an existing external wall the joists can be hung on metal joist hangers which are fixed to a horizontal timber plate wall bolted to the wall. 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. Supporting imposed load. 2002 bs 5268 7 5.

Flat roof joists. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. There are several variables to consider when determining the proper rafter size. These span tables apply only to flat roof and roof with a slope of up to 10 degrees.

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. Structural calculations for timber joists timber beams glulam beams flitch beams using the latest design codes. Calculations to bs 5268 2. Here the number is 941 86 inches.

Flat roof with no permanent access and altitude not exceeding 100m 0 75 kn m udl 0 9 kn point load most areas exceeding 100m but not exceeding 200m excluding parts of scotland pennines north east england refer to bs 6399 3 1 kn m udl 0 9 kn point load. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. Flat roofs timber sizes and construction. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak.

A cavity closer should be provided to the top of the walls to prevent fire spread and to stop damp air entering the roof space. 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. Surveyors span tables for designing roof rafters. Rafter run outer wall this should be measured starting from the center of the roof span and then extending to the very edge of the exterior wall.

For pitched roofs flat roofs and ceiling joists.