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.

Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them. 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. K series joists range in depth from 10 to 30 and can span up to 60. 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.

The range of joist sizes used in homes varies though between 2 by 4 inches and 2 by 12 inches. About o donnell metal deck. These welded steel products are used to support a building s roof and floors. It covers 2 common lumber species and sizes at 20 pounds per square foot load.

The difference in the joist sizes applies to the width of the boards which determines the height of the ceiling. 2 x 12 s are not listed because you can span pretty much whatever you want. This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage. Dead load per square metre in kn m supported by joists.