Maximum Space Between Floor Joists

Joists may cantilever up to of the actual adjacent span.

Maximum space between floor joists.

1 ft 0 3048 m. Most decks use 16 on center spacing for joists. Maximum floor joist span for no. Spanning 16 6 between supports may cantilever up to an additional 4 1 for a total maximum length of 20 7 southern pine deck beam maximum spans.

Some builders reduce joist spacing to 12 on center to strengthen the deck frame or to increase maximum allowable joist spans. This a rough guideline. Live load floor joist span tables in chapter 7 of the state residential code based on the 2012 international residential code. Maximum span of 2x10 floor joist maximum span of 2x12 floor joist the most important design choices to consider when building a home are the species and grade of wood that is being used as well as joist size and spacing.

Most decking is not strong enough to support longer spans than 16. 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. I asked my local building official how he checks a deck plan to make sure the joist size and spacing combination will meet requirements of the building code he goes to the 40 lb. Live load is weight of furniture wind snow and more.

For example 2x6 materials can usually span 24 without any noticeable deflection and still support a significant load. For example a 2 x 12 joist placed 16 oc. Refer to the decking span table to determine what is the maximum distance that your chosen decking can span between joists. 1 psf lb f ft 2 47 88 n m 2.

For a more rigid feel 12 or less may be preferred. Joist spacing for composite decking. Deck joist spacing should never exceed 16 on center with the exception of max deck boards which allow for maximum 24 on center. 2 grade of douglas fir are indicated below.

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. Normally floor joists are spaced 16 inches apart on center. Dead load weight of structure and fixed loads 10 lbs ft 2. The rule of thumb is 6 foot span with a 2 6 on 16 centers.

Builders can adjust their choice of lumber size and spacing depending on circumstances. These elements will greatly affect how far you can span your joists. This means from the center of one upright joist to the center of the next.