Dimensional lumber deck beam span chart.
Max span for 2x6 floor joist.
A double 2x12 beam can span 12 feet.
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.
The larger the deck the larger the joists.
Live load is weight of furniture wind snow and more.
Dead load weight of structure and fixed loads 10 lbs ft 2.
True floor joist span calculations can only be made by a structural engineer or contractor.
While every effort has been made to insure the accuracy of the information presented and special effort has been made to assure that the information reflects the state of the art neither the west coast lumber inspection bureau the american wood council nor its members assume any responsibility for any particular design prepared from this online span calculator.
This chart is for basic reference only.
If you have any questions.
2 grade of douglas fir are indicated below.
In typical deck construction with a ledger on one side of the joist and beam on the other the size of the joists is driven by the size of the deck and based on the general maximum spans mentioned above.
Our joist span charts are for wood joists with a maximum dead load of 10 pounds per square foot and a live load of 40 pounds per square foot.
Maximum floor joist span for no.
1 psf lb f ft 2 47 88 n m 2.
Spans in this table were derived from the irc table r502 3 1 2 design criteria.
For best results refer to our wood and composite deck joist span table.
These tables can also be used to determine deck joist span.
When supporting joists that span 12 feet with no overhang beyond the beam a double ply beam can span in feet a value equal to its depth in inches.
Live load represents the weight of furniture snow etc.
1 ft 0 3048 m.
The numbers in gray indicate the distance between the support posts.
For example in the joist span table below the highlighted cell shows that 2 x 8 southern yellow pine joists that have a grade of 2 and are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.
A 2 2x10 can span 10 feet and so on.
Hem fir 2 joists with a live dead load of 40 10 psf.