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.
Flat roof joist span tables uk.
Joist breadth 47mm.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
Maximum slop3 10 deg.
At least 40mm bearing on supports.
For timber floors between homes.
Supporting imposed load for access and repair only.
Other span tables are based on.
Floor joists flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2.
Flat roof joists rafters purlin.
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.
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.
These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
Tables 1 and 2 in this chapter are derived from the trada technology ltd.
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.
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 pitched roofs flat roofs and ceiling joists.
Span tables for solid timber joists.
This table uses commonly available uk regularised timber depths.
The section sizes are based on regularised als or cls timber.