Flat Roof Joist Span Table 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.

Flat roof joist span table uk.

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. 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. Other span tables are based on.

This should be compared to the table. 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. Surveyors span tables for designing roof rafters. All the figures are based on the normal loading conditions.

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. 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. For timber floors between homes. You need to measure the complete span of your floor joists together with the distance between them the centres and the size of the timbers.

The section sizes are based on regularised als or cls timber. Tables 1 and 2 in this chapter are derived from the trada technology ltd. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Span tables for solid timber joists.

This table uses commonly available uk regularised timber depths. Eurocode 5 span tables for solid timber members in floors ceilings and roofs for dwellings 3rd edition. 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. Floor joist span tables for surveyors floor construction.

The floor joist span tables are based on the loadings given in the amended version of bs 6399 1 which is an imposed load of either a uniformly distributed load of 1 5 kn m or a concentrated load of 1 4 kn. If your old joists do not meet the requirements set by the table they are either supported. For pitched roofs flat roofs and ceiling joists.