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Floor Joists Table

Common Floor Joists Materials - Span Table

These tables state that the given floor joists will not deflect more than 1/360th of the span as long as they are spaced no greater than 16 inches on center and the load will not exceed 40 pounds per square foot (PSF) live loading plus 10 PSF dead load. Span is defined as the greatest distance along the bottom of the joist between supporting beams or columns. If there is any doubt in your mind, contact a structural engineer.

If you are planning a house or a room addition, be sure to consult with a structural engineer. Have him or her specify the actual floor joist size. In addition, ask the engineer to verify that the wood joist delivered to the jobsite is, in fact, the correct material. Look on the side of the joist for the grade and species stamp!

Common Floor Joists Materials-Span Table

Lumber Species 2x6 2x8 2x10 2x12
  .
Southern Yellow Pine #1 Grade 9'-11" 13'-1" 16'-9" 20'-4"

 

Southern Yellow Pine #2 Grade 9'-9" 12'-10" 16'-1" 18'-10"

 

West Coast Douglas Fir #1 9'-11" 13'-1" 16'-5" 19'-1"

 

West Coast Douglas Fir #2 9'-9" 12'-7" 15'-4" 17'-10"

 

Hemlock-Fir #1 Grade 9'-6" 12'-7" 16'-0" 18'-7"

 

Hemlock-Fir #2 Grade 9'-1" 12'-0" 15'-1" 17'-7"

 

Spruce/Pine/Fir Southern #1 8'-10" 11'-8" 14'-10" 17'-7"

 

Spruce/Pine/Fir Southern #2 8'-7" 11'-4" 14'-2" 16'-6"
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