Roof Joist Sizes

These joists easily handle spans that wood systems cannot handle while their lightweight construction makes them much less costly than steel beams.

Roof joist sizes.

Not more than 0 5 more than 0 5 but not more than 0 75 more than 0 75 but not more than 1. Permissible clear span metres. It covers 2 common lumber species and sizes at 20 pounds per square foot load. These welded steel products are used to support a building s roof and floors.

2 x 12 s are not listed because you can span pretty much whatever you want. Dead load per square metre in kn m supported by joists. Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them. For example the highlighted cell below shows that a 2 x 6 southern yellow pine joist with a grade of 2 and spaced 24 apart can have a maximum span of 10 feet 0 inches 10 0 if you are designing your structure to support a plaster ceiling.

Centre to centre spacing of joists in mm joist size width depth mm 400 450 600 400 450 600 400 450 600. About o donnell metal deck. The range of joist sizes used in homes varies though between 2 by 4 inches and 2 by 12 inches. This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage.