Attic Joist Span

This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction.

Attic joist span.

Also available for the android os. As mentioned above the span tables within the code list the allowable ceiling joist spans for common lumber sizes based on what design load scenario is applied. 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. So span length and width between the spans can be determined only by calculations.

Now lets take a look at those tables. For uninhabitable attics without storage we will use table r802 4 1 and for uninhabitable attic with limited storage we will use table r802 4 2. Ceiling joist span tables. It is safe to say though that 2x6 ceiling joists spaced every 24 inches on center a typical arrangement found in attics will not support live loads for a bedroom office or bathroom.

Ceiling joist spans for common lumber species uninhabitable attics with limited storage live load 20 psf l δ 240 check sources for availability of lumber in lengths greater than 20 feet. 1 inch 25 4 mm 1 foot 304 8 mm 1 pound per square foot 0 0479kpa. Span exceeds 26 feet in length.