Roof Joist Sizes

Centre to centre spacing of joists in mm joist size width depth mm 400 450 600 400 450 600 400 450 600.

Roof joist sizes.

2 x 12 s are not listed because you can span pretty much whatever you want. The difference in the joist sizes applies to the width of the boards which determines the height of the ceiling. This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage. A 2 by 4 inch joist for instance hangs into the room by 4 inches which may leave the ceiling high while a 2 by 12 inch joist in the same position hangs 12 inches into the room which decreases the ceiling height by 8 inches.

These joists easily handle spans that wood systems cannot handle while their lightweight construction makes them much less costly than steel beams. 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. Permissible clear span metres. Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them.

It covers 2 common lumber species and sizes at 20 pounds per square foot load. About o donnell metal deck. Not more than 0 5 more than 0 5 but not more than 0 75 more than 0 75 but not more than 1. K series joists range in depth from 10 to 30 and can span up to 60.