Tables 1 and 2 in this chapter are derived from the trada technology ltd.
Flat roof timber span tables 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.
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.
For pitched roofs flat roofs and ceiling joists.
Surveyors span tables for designing roof rafters.
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.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
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.
Span tables for solid timber joists.
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.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
Span tables span tables can be used to determine the size of a timber member of a particular strength class required for a given span.
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.
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.
The section sizes are based on regularised als or cls timber.
Eurocode 5 span tables for solid timber members in floors ceilings and roofs for dwellings 3rd edition.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
All the figures are based on the normal loading conditions.