These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
Flat roof joist span table uk.
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.
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.
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.
If your old joists do not meet the requirements set by the table they are either supported.
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.
For pitched roofs flat roofs and ceiling joists.
Span tables for solid timber joists.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
This table uses commonly available uk regularised timber depths.
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.
Other span tables are based on.
Joists under each partition.
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.
Surveyors span tables for designing roof rafters.
All the figures are based on the normal loading conditions.
Eurocode 5 span tables for solid timber members in floors ceilings and roofs for dwellings 3rd edition.
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.
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.
Tables 1 and 2 in this chapter are derived from the trada technology ltd.
Floor joist span tables for surveyors floor construction.
Flat roof joists rafters purlin.
This should be compared to the table.
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.
