Flat Roof Timber Joist Span

Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.

Flat roof timber joist span.

The lengths and sizes of joists vary depending on the species and quality of the lumber used. Span tables for solid timber joists. You def cant put a joint in the timber. If you want 6 joists you need a steel midway.

One row when the span of the joists exceeds 2 5m. Two rows or more when the span exceeds 4 5m. Rafter and joist span faq. 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 example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine. They also tell you what the maximum spacing should be between each section or timber member 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 05 2 67 3 22 3 77 4 31 4 85 assumptions at 400mm centers. 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. Although i think you can get 6 metre joists in 6 x 2.

The section sizes are based on regularised als or cls timber. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. Joists for that span would normally be around 9. Also available for the android os.

Herringbone type timber 38mm x 38mm. 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. Usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size automatically calculate sizes suitable for supporting the loads below. Strutting should be either.

For timber floors between homes. Tables 1 and 2 in this chapter are derived from the trada technology ltd.