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.
Flat roof joist span c24.
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 47 x 120 2 43 2 39 2 27 47 x 145 3 08 3 02 2 87 47 x 170 3 75 3 67 3 42 47 x 195 4 41 4 31 3 92 47 x 220 5 04 4 85 4 41 75 x 170 4 50 4 38 3 99.
Rafter and joist span faq.
This demo version is fixed at 1m clear span.
1 psf lb f ft 2 47 88 n m 2.
2 are indicated below.
1 enter joist details 1 1 span and joist spacing.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.
Live load is weight of furniture wind snow and more.
Timber floor joists shall be adequate for the spans and loads and be correctly installed.
The full version allows any size.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
Solid timber joist sizes are provided in the bs 8103 3 span tables.
Also available for the android os.
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 04 2 75 3 47 4 20 4 93 5 66 floor joists flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2.
This is the distance between joist centres.
Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.
1 ft 0 3048 m.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
Span calculator for wood joists and rafters also available for the android os.
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.
Flat roof joist calculator.
