Roof Rafter Rafter Span Tables Residential

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.

Roof rafter rafter span tables residential.

Rafter span tables use these two tables for roof rafters with a slope of 3 in 12 or less. Table r802 5 1 2 continued rafter spans for common lumber species roof live load 20 psf ceiling attached to rafters l δ 240 check sources for availability of lumber in lengths greater than 20 feet. The focus is 20 psf live load. These rafter span tables provide the best reference to quickly and easily determine the maximum span for all grades of southern pine according to the 2018 international residential code.

All other data can be found in the 2012 international residential code rafter spans. Straight line interpolation shall be permitted for intermediate spans and design values. 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. So this table could accommodate a house with a total rafter span or house width of 32 feet.

Use these two tables for roof rafters with a slope greater than 3 in 12. These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center. These eight tables are based on 16 o c. Rafter span table and 2012 irc requirements these rafter spans are for 2 lumber a ground snow load of 30 psf the ceiling not attached to rafters and a dead load of 10 psf.

Be sure to use rafter clips on every rafter not nailed into a ceiling joist. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. Applications according to the 2018 international residential code. The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter.

The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. The above spans are based on american softwood lumber standard sizes.