Standard Ceiling Joist Size
Joist span and spacing is set by your local building code.
Standard ceiling joist size. This is a 2 x 4 nailed flat down against the top of the joist perpendicular and right along the center of the span and 2 x 6 or more nailed into it and turned like a joist or blocking bridging or similar x bracing. Track gauge same as stud with 1 track leg height. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
The range of joist sizes used in homes varies though between 2 by 4 inches and 2 by 12 inches. The difference in the joist sizes applies to the width of the boards which determines the height of the ceiling. You should check with your local building department for construction requirements in your area.
Though there is no standard joist size for the ceilings in all buildings most average homes use ceiling joists in a board size of 2 by 6 inches. 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. Table r802 4 1 ceiling joist spans for common lumber species uninhabitable attics without storage live load 10 psf l δ 240.
Ceiling joist spacing in inches 12 16 19 2 24 species and grade of lumber various lumber size options 2 4 2 6 2 8 2 10 the maximum ceiling joist span based on the lumber size species grade and spacing used. Joist spacing in this design mode incorporates different types of wood used in ceiling construction including 2 grades of southern pine douglas fir and hemlock fir types which are the most common. Of stud secured to the stud.
Ceiling joist top flange braced 48. The standard construction of interior framing in a home uses 16 inch on center oc spacing for ceiling joists. If stud height exceeds table web stiffeners are required.
Web at both ends of the stud with four 4 8 pan head. While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length. For other grades and species and for other loading conditions refer to the awc stjr.