This a rough guideline.
Floor joist spans feet and inches.
A 2x8 up to 12 feet.
The larger the deck the larger the joists.
Live load is weight of furniture wind snow and more.
Douglas fir 2 by 10 joists graded as structural select allows joist spans up to 21 feet for a live load of 30 pounds per square foot when spaced 12 inches apart 19 feet 1 inch for 16 inch spacing and 16 feet 8 inches for 24 inch spacing.
The rule of thumb is 6 foot span with a 2 6 on 16 centers.
Span refers to the length of the i joist.
The floor joist spacing is the distance between the centers of any two installed joists.
The l 480 table with a 40 per square foot live load and a 20 per square foot dead load with a depth of 11 7 8 inches will give you spans according to joint weight.
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.
Since the example house we are designing for is 12 feet wide we need to find in the floor joist span table a joist size and centering that can span 12 or wider.
1 ft 0 3048 m.
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.
Maximum floor joist span for no.
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.
2x10 to 15 feet and 2x12 to 18 feet.
1 psf lb f ft 2 47 88 n m 2.
A live load of 60 pounds per square foot demands more support and shorter spans.
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.
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.
With these factors the lightest joist will have a maximum span of 17 feet 8 inches.
In general terms joists spaced 16 inches on center can span 1 5 times in feet their depth in inches.
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.
Span entries are listed for 2 6 through 2 12 joists and 12 in 16 in and 24 in.
See the image below for an example of joists spaced 16 on center 16 o c.
2 grade of douglas fir are indicated below.
True floor joist span calculations can only be made by a structural engineer or contractor.
However when running spf 2 6 floor joists into the floor joist calculator referenced above you get a maximum span of 9 feet 8 inches with a minimum bearing length of 3 inches at each end on 12 centers.
