Flat Roof Joist Span Tables Uk

All roof timbers including joists wall plates blocking strutting battens firings and noggings must be to be preservative treated unless the timber used is naturally durable.

Flat roof joist span tables uk. 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. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. The joists should be sized using either the trada span tables or bs en 1995. The section sizes are based on regularised als or cls timber.

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. Span tables for solid timber joists. Joists under each partition. 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.

Eurocode 5 span tables for solid timber members in floors ceilings and roofs for dwellings 3rd edition. For pitched roofs flat roofs and ceiling joists. All the figures are based on the normal loading conditions. 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.

Tables 1 and 2 in this chapter are derived from the trada technology ltd. Floor joist span tables for surveyors floor construction. Surveyors span tables for designing roof rafters. This should be compared to the table.

Due to variations in timber grades load sets support conditions and bearing widths the tables are not suitable as a design tool. 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. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. 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.

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.