Flat Roof Timber Sizes Uk

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.

Flat roof timber sizes uk. 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. C16 timber is commonly used in floor and roof joists for intern. 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. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak.

All the figures are based on the normal loading conditions. 2002 bs 5268 7 5. Order helpline 01752 692 760. Automatically calculate suitable rafter sizes enter a specific rafter size.

Here the number is 1166 66 inches. Here the number is 941 86 inches. For pitched roofs flat roofs and ceiling joists. 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.

Supporting imposed load. Structural calculations for timber joists timber beams glulam beams flitch beams using the latest design codes. 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. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.

Calculations to bs 5268 2. Flat roof joists. 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. Subject ceilings and flat roofs timber sizes and construction details 09 issued 01 04 13 rev page 1 of 2 the following tables give details of the allowable spans and spacing for some of the more common timber sizes used in ceiling and flat roof construction.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Should refer to trada document span tables for solid timber members in floors ceilings and roofs excluding trussed rafter roofs for dwellings or ask your lbc surveyor for advice.