Use these tables to establish lengths, sizes and spacing of rafters based on a range of factors such as, grade, spacing and pitch.  Explore the tables we added below to help you in your DIY projects. Rafter Span, Roof Beam Span, Ceiling Joist Span, Floor Joist Span and Floor Beam Span. We recommend you check with your local building inspector to determine whether your local code isn’t different.

 

                                            RAFTER TABLE

                                                                                       

 RAFTER SIZE 

RAFTER SPACING

ON CENTER                                      

 MAXIMUM SPAN

2” X 4”                                     

12”

8’-10”

 

16”          

8’-0”

 

24”         

6’-7”

2” X 6”                                     

12”

13’-7”

 

16”          

11’-9”

 

24”         

9’-7”

2” X 8”                                     

12”

17’-2”

 

16”          

14’-11”

 

24”         

12’-2”

2” X 10”                                     

12”

21’-0”

 

16”          

18’-2”

 

24”         

14’-10”

2” X 12”                                     

12”

24’-4”

 

16”          

21’-1”

 

24”         

17’-3”

Spans in this table were derived from the 2006 IRC and the SpanMaster calculator.

Design Criteria: Hem-Fir #2 rafters with a live/dead loading of 30/10 psf. DOL 1.15; L / 180.

                                    

                                      ROOF BEAM TABLE

                                                    BEAM SPAN BETWEEN SUPPORTS ( SPACING OF POSTS)

                                      4’                 5’                 6’                 7’                  8’                 9’                 10’               11’                12’

  R         

  A          4'

  F           5’

  T          6'

  E          7'

  R          8'

              9'

  S        10'

  P        11'

  A        12'

  N 

 

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

 

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x6

 

2-2x4

2-2x4

2-2x4

2-2x4

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

 

2-2x4

2-2x4

2-2x4

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

 

2-2x4

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x8

2-2x8

 

2-2x6

2-2x6

2-2x6

2-2x6

2-2x8

2-2x8

2-2x8

2-2x8

2-2x8

 

2-2x6

2-2x6

2-2x6

2-2x8

2-2x8

2-2x8

2-2x8

2-2x10

2-2x10

 

2-2x6

2-2x6

2-2x8

2-2x8

2-2x8

2-2x10

2-2x10

2-2x10

2-2x10

 

2-2x6

2-2x8

2-2x8

2-2x8

2-2x10

2-2x10

2-2x10

2-2x12

2-2x12

Design Criteria: Hem-Fir #2 beam members with a live/dead loading of 30/10 psf.

DOL 1.15; L / 240. (Derived from SpanMaster)

                                                                              

                                     CEILING JOIST TABLE    (NO STORAGE)

 

 JOIST SIZE

JOIST SPACING

ON CENTER

MAXIMUM SPAN

2” X 4”

12”

11’-7”

 

16”

10’-6”

 

24”

9’-2”

2”x6”

12”

18’-2”

 

16”

16’-6”

 

24”

14’-5”

2”x8”

12”

24’-0”

 

16”

21’-9”

 

24”

18’-6”

2”x10”

12”

30’-7”

 

16”

27’-8”

 

24”

22’-7”

2”x12”

12”

37’-1”

 

16”

32’-1”

 

24”

26’-3”

Spans in this table were derived from the 2006 IRC and the SpanMaster calculator.

Design Criteria: Hem-Fir #2 supporting drywall ceiling and live/dead loading of 10/5 psf.

DOL 1.00; L / 240. (Uninhabitable attics without storage)

                                  

                                     CEILING JOIST TABLE     (WITH LIMITED STORAGE)

 

 JOIST SIZE 

JOIST SPACING

ON CENTER

 MAXIMUM SPAN

2”x4”

12”

9’-2”

 

16”

8’-4”

 

24”

7’-1”

2”x6”

12”

14’-5”

 

16”

12’-8”

 

24”

10’-4”

2”x8”

12”

18’-6”

 

16”

16’-0”

 

24”

13’-1”

2”x10”

12”

22’-7”

 

16”

19’-7”

 

24”

16’-0”

2”x12”

12”

28’-9”

 

16”

22’-8”

 

24”

20’-4”

Spans in this table were derived from the 2006 IRC and the SpanMaster calculator.

Design Criteria: Hem-Fir #2 supporting drywall ceiling and live/dead loading of 20/5 psf. DOL 1.00; L / 240.

                                     

                                     FLOOR JOIST TABLE

 

 JOIST SIZE

JOIST SPACING 

ON CENTER

 MAXIMUM SPAN

2”x4”

12”

6’-4”

 

16”

5’-9”

 

24”

5’-1”

2”x6”

12”

10’-0”

 

16”

9’-1”

 

24”

7’-11”

2”x8”

12”

13’-2”

 

16”

12’-0”

 

24”

10’-2”

2”x10”

12”

16’-10”

 

16”

15’-2”

 

24”

12’-5”

2”x12”

12”

20’-4”

 

16”

17’-7”

 

24”

14’-4”

Spans in this table were derived from the 2006 IRC and the SpanMaster calculator.

Design Criteria: Hem-Fir #2 joists with a live/dead load of 40/10 psf. DOL 1.00; L / 360.

                                  

                                      FLOOR BEAM TABLE

 

                                                          BEAM SPAN BETWEEN SUPPORTS ( SPACING OF POSTS)

                                     4’                  5’                 6’                  7’                  8’                  9’                10’                 11’              12’

          

  J         4’

  O        5'

  I          6'

  S        7'

  T         8’

  S        9’

  P      10'

  A       11'

  N       12'

 

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

 

2-2x4

2-2x4

2-2x4

2-2x4

2-2x4

2-2x6

2-2x6

2-2x6

2-2x6

 

2-2x4

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

 

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x6

2-2x8

2-2x8

2-2x8

 

2-2x6

2-2x6

2-2x6

2-2x6

2-2x8

2-2x8

2-2x8

2-2x8

2-2x10

 

2-2x6

2-2x6

2-2x8

2-2x8

2-2x8

2-2x10

2-2x10

2-2x10

2-2x10

 

2-2x6

2-2x8

2-2x8

2-2x8

2-2x10

2-2x10

2-2x10

2-2x12

2-2x12

 

2-2x8

2-2x8

2-2x10

2-2x10

2-2x10

2-2x12

2-2x12

2-2x12

3-2x10

 

2-2x8

2-2x10

2-2x10

2-2x10

2-2x12

2-2x12

2-2x12

3-2x10

3-2x10

Design Criteria: Hem-Fir #2 beam members with a live/dead loading of 40/10 psf.

DOL 1.00; L / 360. (Derived from SpanMaster)

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