I- Joist Span Charts

Floor Span Tables:  I-Joist Simple Span Applications

To Use: 

 1.        Select the appropriate table based on the project design loads
 2.
        Find a span that meets or exceeds the design span.
 3.
        Read the corresponding joist series, depth, and spacing.

 Caution:  For floor systems that require both simple and continuous span joists, it is a good idea to check both tables before selecting a joist.  Some conditions are controlled by simple span deflection rather than continuous span strength.

 

40 PSF LIVE LOAD; 10 PSF DEAD LOAD @ L/480

Depth

Series

Without Web Stiffeners

 

 

12 O.C

16 O.C.

19.2 O.C.

24 O.C.

9 1/2"

LPI 20x

18'-1"

16'-6

15'-9"

14'-9"

 

 

 

 

 

 

11 7/8

LPI 20x

21'-5"

19'-7"

18'-7"

16'-11"

 

 

 

 

 

 

14

LPI 20x

24'-3"

22'-1"

21'-0"

18'-10"

 

LPI 32

25'-0"

22'-8"

21'-5"

19'-11"

16

LPI 42

31'-4"

28'-6"

26'-11"

25'-1"

40 PSF LIVE LOAD; 15 PSF DEAD LOAD @ L/480

Depth

Series

Without Web Stiffeners

 

 

12 O.C

16 O.C.

19.2 O.C.

24 O.C.

9 1/2"

LPI 20x

18'-1"

16'-6"

15'-9"

14'-1"

 

 

 

 

 

 

11 7/8

LPI 20x

21'-5"

19'-7"

18'-0"

16'-1"

 

 

 

 

 

 

14

LPI 20x

24'-3"

22'-0"

20'-1"

17'-11"

 

LPI 32

25'-0"

22'-8"

21'-5"

19'-9"

16

LPI 42

31'-4"

28'-6"

26'-11"

23'-2"

40 PSF LIVE LOAD; 25 PSF DEAD LOAD @ L/ 480

Depth

Series

Without Web Stiffeners

 

 

12 O.C

16 O.C.

19.2 O.C.

24 O.C.

9 1/2"

LPI 20x

18'-1"

15'-10"

14'-6"

12'-11"

 

 

 

 

 

 

11 7/8

LPI 20x

21'-0"

18'-2"

16'-7"

14'-10"

 

 

 

 

 

 

14

LPI 20x

23'-4"

20'-2"

18'-5"

16'-6"

 

LPI 32

25'-0"

22'-7"

20'-8"

16'-8

16

LPI 42

31'-4"

28'-6"

24'-6"

19'-7"

 

Design Assumptions:

    1.     The spans listed are for clear spans between supports.
    2.  
    The spans are based on uniform loads only.
    3.
            Live load deflection has been limited to L/480.
    4.
            Total deflection has been limited to L/240.  Those spans that exceed of total deflection are shown in bold.
    5.
            A load sharing (repetitive member) increase has been applied.  This increase is based on the attachment of a proper deck to three or more joists, spaced no more than 24 O.C.
    6.
            The spans are based on the minimum required bearings.
    7.
            The tables shown do not include web stiffeners.

 Additional notes:

     1.      The design of continuous spans is based on the longest span.  The shortest span must not be less than 50% of the longest span.
    2.
            These spans are not evaluated for vibration.
    3.
            Bridging, Blocking, a direct applied ceiling and/or bottom flange bracing, though not required for vertical load capacity, can improve floor vibration and bounce.
    4.
            For conditions not shown, use the Uniform Floor Load (PLF) tables or contact TruLine Truss, Inc. for assistance.