Floor Joist Spans Feet And Inches

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.

Floor joist spans feet and inches.

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. See the image below for an example of joists spaced 16 on center 16 o c. 1 ft 0 3048 m. 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.

A live load of 60 pounds per square foot demands more support and shorter spans. 2x10 to 15 feet and 2x12 to 18 feet. The larger the deck the larger the joists. The floor joist spacing is the distance between the centers of any two installed joists.

Live load is weight of furniture wind snow and more. The rule of thumb is 6 foot span with a 2 6 on 16 centers. 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.

Span entries are listed for 2 6 through 2 12 joists and 12 in 16 in and 24 in. Span refers to the length of the i joist. 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. 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.

This is the most common as the typical span is 15 feet. 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. 1 psf lb f ft 2 47 88 n m 2. 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.

With these factors the lightest joist will have a maximum span of 17 feet 8 inches. Maximum floor joist span for no. 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. 2 grade of douglas fir are indicated below.

In general terms joists spaced 16 inches on center can span 1 5 times in feet their depth in inches. A 2x8 up to 12 feet. Joist span and spacing is set by your local building code.