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.
Timber span tables flat roof.
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.
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.
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.
They also tell you what the maximum.
These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
For pitched roofs flat roofs and ceiling joists.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
Flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2.