Roofing Table Rafter Span

For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.

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. The tables below give maximum spans for rafters and beams. 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. Maximum rafter spans for a patio roof.

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. Rafter spans are tabulated for the most common roof loads. So this table could accommodate a house with a total rafter span or house width of 32 feet. This rafter span calculator is species specific for douglas fir hemlock etc.

Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. The loads are based on adjusted roof snow loads from the governing building code. 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.

Tables listing maximum spans for southern pine joists and rafters are detailed below. This is based upon the span of the rafter horizontal span not total rafter length live and dead loads. To size joists and rafters use the maximum span tables for southern yellow pine.