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.
Roof rafter rafter span tables residential.
These eight tables are based on 16 o c.
Rafter span tables use these two tables for roof rafters with a slope of 3 in 12 or less.
1 inch 25 4 mm 1 foot 304 8 mm 1 pound per square foot 0 0479 kpa.
Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.
Be sure to use rafter clips on every rafter not nailed into a ceiling joist.
Applications according to the 2018 international residential code.
The above spans are based on american softwood lumber standard sizes.
All other data can be found in the 2012 international residential code rafter spans.
The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter.
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.
Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.
Use these two tables for roof rafters with a slope greater than 3 in 12.
Straight line interpolation shall be permitted for intermediate spans and design values.
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.
These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center.
So this table could accommodate a house with a total rafter span or house width of 32 feet.
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.
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.
