Roof Rafter Rafter Span Tables Residential

Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.

Roof rafter rafter span tables residential.

The 2015 span tables for joists and rafters updates the 2012 edition and provides a simplified system for determining allowable joist and rafter spans for typical loads encountered in one and two family dwellings and is referenced in the 2015 international building code and 2015 international residential code. These eight tables are based on 16 o c. The above spans are based on american softwood lumber standard sizes. 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 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. All other data can be found in the 2012 international residential code rafter spans. 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.

Be sure to use rafter clips on every rafter not nailed into a ceiling joist. Straight line interpolation shall be permitted for intermediate spans and design values. Use these two tables for roof rafters with a slope greater than 3 in 12. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.

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. 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. 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.

Applications according to the 2018 international residential code. 1 inch 25 4 mm 1 foot 304 8 mm 1 pound per square foot 0 0479 kpa.