Table 9 2 adjustment factors for alternate loading and spacing conditions for determining required com pression perpendicular to grain design values f c for joists and rafters.
Longest span of 2 x 10 floor joists.
The numbers in gray indicate the distance between the support posts.
When building a house or even a deck it is important to confirm you have the correct joist sizes spans and spacing before you get started.
Live load is weight of furniture wind snow and more.
2 grade of douglas fir are indicated below.
Dead load weight of structure and fixed loads 10 lbs ft 2.
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.
For example a joist made from doubled 2 x 6s can span a distance about 25 percent more than a single 2 x 6 but a 2 x 12 can span about 80 percent more than a 2 x 6 even though it has the same amount of wood as a doubled 2 x 6.
Joist span and spacing is set by your local building code.
Span entries are listed for 2 6 through 2 12 joists and 12 in 16 in and 24 in.
At 16 inch spacing 15 feet 2 inches and 13 feet 3 inches at 24 inch spacing.
While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length.
1 ft 0 3048 m.
Span calculator for wood joists and rafters also available for the android os.
Also available for the android os.
Use a joist span table such as those found in the resources section to determine the maximum 2 by 10 joist spans for other species and lumber grades.
A double 2x12 beam can span 12 feet.
The maximum span for a 2 x 10 floor joist is up to 21 feet depending on several factors.
Spaced at 12 inches the joist may only span 16 feet 8 inches.
4 see a 1 3 for 2 span floor joist requirements.
Additionally the load that the floor needs to support is also a consideration.
Live dead 12 16 19 2 24 10 5 0 23 0 30 0 36 0 45 20 10 0 45 0 60 0 72 0 90 30 10.
A 2 2x10 can span 10 feet and so on.
1 psf lb f ft 2 47 88 n m 2.
These tables can also be used to determine deck joist span.
The width is considerably more important than the thickness of a board.
One must take into consideration the spacing of the joists and type of wood used.
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.
The illustrations one for cantilever joists and one for flush rim beam hung joists point out where joist span measurements are taken from the saddle of the ledger mounted joist hanger to the center of a dropped beam or saddle of the.