Rafter Span Roof Joist Span Chart

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.

Rafter span roof joist span chart.

If you have a single sloped roof then the 11 span distance for 2 4 rafters o c. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. Means that your shed should be no wider or longer depending on how you orientate your single sloped roof than 11.

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. Span ft 1 5 2 0 2 5 3 0 3 5 2 30 22 18 15 13 4 59 44 36 30 25 6 89 67 53 44 38 8 119 89 71 59 51 10 148 111. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.

For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. Also available for the android os. Surveyors span tables for designing roof rafters.

Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. 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. View joist rafter tables.

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. Therefore for gable roofed sheds the rafter span table is indicating how far a rafter can span half of your shed s width.