View joist rafter tables.
Timber flat roof joist span tables.
Span calculator for wood joists and rafters also available for the android os.
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.
Flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2.
Simplified span tables for southern pine lumber and glued laminated timber glulam headers beams and girders.
Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.
Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs.
At least 40mm bearing on supports.
Joist breadth 47mm.
Where the tables do not apply or where there are concentrated loads floor joists should be designed by an engineer in accordance with technical requirement r5.
Span is clear span between supports.
For simple construction such as domestic construction this can be determined from span table supplements in as1684 2 and as1684 3.
Also available for the android os.
Timber floor joists shall be adequate for the spans and loads and be correctly installed.
These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
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.
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.
For pitched roofs flat roofs and ceiling joists.
Maximum slop3 10 deg.
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.
Other more complex load condition spans can be determined with our free hyne timber design 7 5 software.
Solid timber joist sizes are provided in the bs 8103 3 span tables.
Supporting imposed load for access and repair only.
View allowable load tables.
Surveyors span tables for designing roof rafters.
