Roofing Table Rafter Span

This is based upon the span of the rafter horizontal span not total rafter length live and dead loads.

Roofing table rafter span.

The spans in this table are based on a maximum supported rafter span of 16 feet where the supported span is the total horizontal distance spanned by the roof rafters divided in half not the diagonal distance or the length of the rafter. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. These 46 tables are based upon design values for visually graded southern pine dimension lumber that became effective june 1 2013. In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.

The loads are based on adjusted roof snow loads from the governing building code. So this table could accommodate a house with a total rafter span or house width of 32 feet. Rafter span tables for surveyors roof construction surveyors span tables for designing roof rafters for pitched roofs flat roofs and ceiling joists 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. 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.

The tables below give maximum spans for rafters and beams. Tables listing maximum spans for southern pine joists and rafters are detailed below. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. For roof live loads less than 20 pounds per square foot psf rafter spans and required e values tabulated for 20 psf shall be permitted to be adjusted in accordance with the fol lowing table.

For each application a pdf download is available. Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. Rafter spans are tabulated for the most common roof loads.