Attic Joist Span

So span length and width between the spans can be determined only by calculations.

Attic joist span.

Span length is different for every room. 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. True floor joist span calculations can only be made by a structural engineer or contractor.

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. Also available for the android os. Ceiling joist span 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.

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. 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. Now lets take a look at those tables.