What Size Floor Joist For A 12 Foot Span

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.

What size floor joist for a 12 foot span. Two options that arise could be your wider 24 and your narrower 12 options for spacing. True floor joist span calculations can only be made by a structural engineer or contractor. 2 8 s come standard at 1 inch thick. Floor joist span tables for various sizes and species of wood.

2x10 to 15 feet and 2x12 to 18 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. Dead load weight of structure and fixed loads 10 lbs ft 2. If you have any questions.

These include the length of the span as well as the type and grade of the lumber being used. 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. 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. In general terms joists spaced 16 inches on center can span 1 5 times in feet their depth in inches.

2x8s are used frequently for these projects. Dead load is the weight of the structure and any fixed items. Live load is weight of furniture wind snow and more. Reading the table you ll see that 2 x 8s installed 16 apart on center can span 12 4.

2 grade of douglas fir are indicated below. So our house would look like the picture below with all floor joists 2 x 8. 1 ft 0 3048 m. Joist span table use these tables to determine floor joist spans based on grade of lumber size of joist floor joist spacing and a live load of 30 lbs ft 2 or 40 lbs ft 2 these tables can also be used to determine deck joist span.

Choosing the correct floor joist size depends on your building application joist spacing and several other factors. Maximum floor joist span for no. Live load 30 lbs ft 2 1436 n m 2. The larger the deck the larger the joists.

A 2x8 up to 12 feet. 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. 1 psf lb f ft 2 47 88 n m 2. Span entries are listed for 2 6 through 2 12 joists and 12 in 16 in and 24 in.

Use these two tables for. 1 in 25 4 mm. In this situation your floor joist will be required to be 12 or 24 inches apart on center. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that 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.